Why Svelte is converting TypeScript to JSDoc

#​638 — May 11, 2023

Read on the Web

JavaScript Weekly

The JavaScript Ecosystem is Delightfully Weird — There are plenty of examples of how JavaScript is weird but Sam focuses on the why. If you’ve been a JS developer for many years you’ll have seen it go through many phases and morph to fit its environment. Sam paints the big picture, concluding with a talk Dan Abramov gave yesterday called “React from Another Dimension.”

Sam Ruby

The New JS Features Coming in ECMAScript 2023 — The next JavaScript update brings smaller additions familiar from other languages, but there are more significant developments waiting in the wings. 

Mary Branscombe (The New Stack)

Full Stack for Front-End Engineers with Jem Young (Netflix) — Learn what it means to become a well-rounded full-stack engineer with this hands-on video course. You’ll dive into servers, work with the command line, understand networking and security, set up continuous integration and deployment, manage databases, build containers, and more.

Frontend Masters sponsor

Vue 3.3 ‘Rurouni Kenshin’ Released — Named after a popular manga series, the latest release of Vue is focused on developer experience improvements, particular for those using TypeScript.

Evan You

John Komarnicki says ▶️ Vue 3.3’s defineModel macro will change the way you write your components.

Next.js 13.4 Released — Despite the minor version bump, this is a big release for the popular React framework. The new app router and its improved approach to filesystem based routing is now offered as a stable feature, with a new concept of server actions being introduced in alpha as a way to mutate data on the server without needing to create an in-between API layer.

Tim Neutkens and Sebastian Markbåge

⚡️ IN BRIEF:

???? Svelte is converting from TypeScript to JSDoc (example).. sort of. Rich Harris popped up on Hacker News to provide some all important context but the ultimate result will be smaller package sizes and a better experience for Svelte’s maintainers.

React now has official ‘canary’ releases if you want to use newer features than in the stable releases but still be on an officially supported channel.

Newly released Firefox 113 lets you override JS files in its debugger.

No stranger to controversy, Ruby on Rails’s David Heinemeier Hansson (DHH) tweeted: ???? “TypeScript sucked out much of the joy I had writing JavaScript.”

RELEASES:

Glint 1.0 – TypeScript powered tooling for Glimmer / Ember templates.

Elementary 2.0 – JS/C++ library for building audio apps.

???? Articles & Tutorials

ES2023’s New Array Copying Methods — The newest ECMAScript spec introduces some new methods on Array that you’ll eventually find useful in your own programs. Phil gives us the tour.

Phil Nash

Private Class Fields Considered Harmful“As a library author, I’ve decided to avoid private class fields from now on and gradually refactor them out of my existing libraries.” Why? Well, that’s the interesting part..

Lea Verou

▶  I’m Done with React — Going from least-to-most important, the reasons this developer isn’t choosing React for future projects make for interesting watching, particularly if you too are overwhelmed by upheaval in the React world. Solid is one of the alternatives he has warmed to.

Adam Elmore

Constraining Language Runtimes with Deterministic Execution — Explore various challenges encountered while using different language runtimes to execute workflow code deterministically.

Temporal Technologies sponsor

Running JavaScript in Rust with Deno — Deno’s use of Rust makes it a natural choice if you’re building a Rust app and want to integrate a JavaScript engine.

Austin Poor

Regular Expressions in JavaScript — Powerful but often misunderstood, many will benefit from this roundup of the potential regexes offer to JavaScript developers.

Adebayo Adams

How to Measure Page Loading Time with the Performance API — The Performance API is a group of standards used to measure the performance of webapps supported in most modern browsers.

Silvestar Bistrović

How to Build a JS VST or Audio Unit Plugin on macOS — VSTs and Audio Units are both types of audio plugins for audio editing software and they’re usually built in C or C++. This tutorial doesn’t dig into the audio side of things, but more the practicalities of packaging things up to get started.

Chris Mendez

An Introduction to the Bun Runtime — If you’ve not yet played with the newest entrant into the JS runtime space, this is a high level overview.

Craig Buckler

2023 State of the Java Ecosystem

New Relic sponsor

Configuring ESLint, Prettier, and TypeScript Together

Josh Goldberg

DestroyRef: Your New Angular 16 Friend

Ion Prodan

Why Astro is My Favorite Framework

Ryan Trimble

???? Code & Tools

file-type 18.4: Detect the File Type of a Buffer, Uint8Array or ArrayBuffer — For example, give it the raw data from a PNG file, and it’ll tell you it’s a PNG file. Uses magic numbers so is targeted solely at non text-based formats.

Sindre Sorhus

Learn How the Rising Trend of Malicious Packages Can Affect Your Apps — Keep your applications secure with Snyk’s article on the increasing number of malicious OS packages and ways to mitigate these risks.

Snyk sponsor

Livefir: Build Reactive HTML Apps with Go and Alpine.js — Go isn’t a language that often pops up in the context of the frontend, but this is a neat integration between Go on the backend and Alpine.js up front.

Adnaan Badr

JZZ.js: A Developer Friendly MIDI library — For both browsers and Node, JZZ.js provides an abstraction over working with MIDI related concepts. There are many examples, but the easter egg in the top left is our favorite.

Sema / Jazz-Soft

htmlparser2 9.0: A ‘Fast and Forgiving’ HTML and XML Parser — Consumes documents and calls callbacks, but it can generate a DOM as well. Works in both Node and browser.

Felix Böhm

cRonstrue: Library to Convert cron Expressions into Human-Readable Form — Given something like */5 * * * *, it’ll return “Every 5 minutes”. No dependencies.

Brady Holt

Knip: Find Unused Files, Dependencies and Exports in TypeScript Projects — Being Dutch for “snip” is appropriate as Knip can trim away things that aren’t being used in your project.

Lars Kappert

jsPlumb 6.1
↳ Visual connectivity for webapps.

gridstack.js 8.1
↳ Build interactive dashboards quickly.

???? Jobs

Find JavaScript Jobs with Hired — Hired makes job hunting easy-instead of chasing recruiters, companies approach you with salary details up front. Create a free profile now.

Hired

Team Lead Web Development — Experienced with Node, React, and TS? Join us and lead a motivated team of devs and help grow and shape the future of our web app focused on helping millions explore the outdoors.

Komoot

????‍???? Got a job listing to share? Here’s how.

???? Don’t tell Satya Nadella..

Fake Windows 11 in Svelte — This is a cute little side project, and the code is available too. The most common complaint I’ve seen is that it’s actually more responsive than the real Windows.. ???? Be sure to check out both ‘VS Code’ and ‘Microsoft Edge’ in this environment.

Yashash Pugalia

???? Prefer Windows XP? Maybe RebornXP is more for you. Complete with the classic starting up sound!

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Announcing General Availability of Amazon CodeCatalyst

We are pleased to announce that Amazon CodeCatalyst is now generally available. CodeCatalyst is a unified software development service that brings together everything teams need to get started planning, coding, building, testing, and deploying applications on AWS. CodeCatalyst was designed to make it easier for developers to spend more time developing application features and less time setting up project tools, creating and managing continuous integration and continuous delivery (CI/CD) pipelines, provisioning and configuring various development and deployment environments, and onboarding project collaborators. You can learn more and get started building in minutes on the AWS Free Tier at the CodeCatalyst website.

Launched in preview at AWS re:Invent in December 2022, CodeCatalyst provides an easy way for professional developers to build and deploy applications on AWS. We built CodeCatalyst based on feedback we received from customers looking for a more streamlined way to build using DevOps best practices. They want a complete software development service that lets them start new projects more quickly and gives them confidence that it will continue delivering a great long term experience throughout their application’s lifecycle.

Do more of what you love, and less of what you don’t

Starting a new project is an exciting time of imagining the possibilities: what can you build and how can you enable your end users to do something that wasn’t possible before? However, the joy of creating something new can also come with anxiety about all of the decisions to be made about tooling and integrations. Once your project is in production, managing tools and wrangling project collaborators can take your focus away from being creative and doing your best work. If you are spending too much time keeping brittle pipelines running and your teammates are constantly struggling with tooling, the day to day experience of building new features can start to feel less than joyful.

That is where CodeCatalyst comes in. It isn’t just about developer productivity – it is about helping developers and teams spend more time using the tools they are most comfortable with. Teams deliver better, more impactful outcomes to customers when they have more freedom to focus on their highest-value work and have to concern themselves less with activities that feel like roadblocks. Everything we do stems from that premise, and today’s launch marks a major milestone in helping to enable developers to have a better DevOps experience on AWS.

How CodeCatalyst delivers a great experience

There are four foundational elements of CodeCatalyst that are designed to help minimize distraction and maximize joy in the software development process: blueprints for quick project creation, actions-based CI/CD automation for managing day-to-day software lifecycle tasks, remote Dev Environments for a consistent build experience, and project and issue management for a more streamlined team collaboration.

Blueprints get you started quickly. CodeCatalyst blueprints set up an application code repository (complete with a working sample app), define cloud infrastructure, and run pre-configured CI/CD workflows for your project. Blueprints bring together the elements that are necessary both to begin a new project and deploy it into production. Blueprints can help to significantly reduce the time it takes to set up a new project. They are built by AWS for many use cases, and you can configure them with the programming languages and frameworks that you need both for your application and the underlying infrastructure-as-code. When it comes to incorporating existing tools like Jira or GitHub, CodeCatalyst has extensions that you can use to integrate them into your projects from the beginning without a lot of extra effort. Learn more about blueprints.

“CodeCatalyst helps us spend more time refining our customers’ build, test, and deploy workflows instead of implementing the underlying toolchains,” said Sean Bratcher, CEO of Buildstr. “The tight integration with AWS CDK means that definitions for infrastructure, environments, and configs live alongside the applications themselves as first-class code. This helps reduce friction when integrating with customers’ broader deployment approach.”

Actions-based CI/CD workflows take the pain out of pipeline management. CI/CD workflows in CodeCatalyst run on flexible, managed infrastructure. When you create a project with a blueprint, it comes with a complete CI/CD pipeline composed of actions from the included actions library. You can modify these pipelines with an action from the library or you can use any GitHub Action directly in the project to edit existing pipelines or build new ones from scratch. CodeCatalyst makes composing these actions into pipelines easier: you can switch back and forth between a text-based editor for declaring which actions you want to use through YAML and a visual drag-and-drop pipeline editor. Updating CI/CD workflows with new capabilities is a matter of incorporating new actions. Having CodeCatalyst create pipelines for you, based on your intent, means that you get the benefits of CI/CD automation without the ongoing pain of maintaining disparate tools.

“We needed a streamlined way within AWS to rapidly iterate development of our Reading Partners Connects e-learning platform while maintaining the highest possible quality standards,” said Yaseer Khanani, Senior Product Manager at Reading Partners. “CodeCatalyst’s built-in CI/CD workflows make it easy to efficiently deploy code and conduct testing across a distributed team.”

Automated dev environments make consistency achievable A big friction point for developers collaborating on a software project is getting everyone on the same set of dependencies and settings in their local machines, and ensuring that all other environments from test to staging to production are also consistent. To help address this, CodeCatalyst has Dev Environments that are hosted in the cloud. Dev Environments are defined using the devfile standard, ensuring that everyone working on a project gets a consistent and repeatable experience. Dev Environments connect to popular IDEs like AWS Cloud9, VS Code, and multiple JetBrains IDEs, giving you a local IDE feel while running in the cloud.

“Working closely with customers in the software developer education space, we value the reproducible and pre-configured environments Amazon CodeCatalyst provides for improving learning outcomes for new developers. CodeCatalyst allows you to personalize student experiences while providing facilitators with control over the entire experience.” said Tia Dubuisson, President of Belle Fleur Technologies.

Issue management and simplified team onboarding streamline collaboration. CodeCatalyst is designed to help provide the benefits of building in a unified software development service by making it easier to onboard and collaborate with teammates. It starts with the process of inviting new collaborators: you can invite people to work together on your project with their email address, bypassing the need for everyone to have an individual AWS account. Once they have access, collaborators can see the history and context of the project and can start contributing by creating a Dev Environment.

CodeCatalyst also has built-in issue management that is tied to your code repo, so that you can assign tasks such as code reviews and pull requests to teammates and help track progress using agile methodologies right in the service. As with the rest of CodeCatalyst, collaboration comes without the distraction of managing separate services with separate logins and disparate commercial agreements. Once you give a new teammate access, they can quickly start contributing.

New to CodeCatalyst since the Preview launch

Along with the announcement of general availability, we are excited to share a few new CodeCatalyst features. First, you can now create a new project from an existing GitHub repository. In addition, CodeCatalyst Dev Environments now support GitHub repositories allowing you to work on code stored in GitHub.

Second, CodeCatalyst Dev Environments now support Amazon CodeWhisperer. CodeWhisperer is an artificial intelligence (AI) coding companion that generates real-time code suggestions in your integrated development environment (IDE) to help you more quickly build software. CodeWhisperer is currently supported in CodeCatalyst Dev Environments using AWS Cloud 9 or Visual Studio Code.

Third, Amazon CodeCatalyst recently added support to run workflow actions using on-demand or pre-provisioned compute powered by AWS Graviton processors. AWS Graviton Processors are designed by AWS to deliver the best price performance for your cloud workloads running in Amazon Elastic Compute Cloud (Amazon EC2). Customers can use workflow actions running on AWS Graviton processors to build applications that target Arm architecture, create multi-architecture containers, and modernize legacy applications to help customers reduce costs.

Finally, the library of CodeCatalyst blueprints is continuously growing. The CodeCatalyst preview release included blueprints for common workloads like single-page web applications, serverless applications, and many others. In addition, we have recently added blueprints for Static Websites with Hugo and Jekyll, as well as Intelligent Document Processing workflows.

Learn more about CodeCatalyst at Developer Innovation Day

Next Wednesday, April 26th, we are hosting Developer Innovation Day, a free 7-hour virtual event that is all about helping developers and teams learn to be productive, and collaborate, from discovery to delivery to running software and building applications. Developers can discover how the breadth and depth of AWS tools and the right practices can unlock your team’s ability to find success and take opportunities from ideas to impact.

CodeCatalyst plays a big part in Developer Innovation Day, with five sessions designed to help you see real examples of how you can spend more time doing the work you love best! Get an overview of the service, see how to deploy a working static website in minutes, collaborating effectively with teammates, and more.

Try CodeCatalyst

Ready to try CodeCatalyst? You can get started on the AWS Free Tier today and quickly deploy a blueprint with working sample code. If you would like to learn more, you can read through a collection of DevOps blogs about CodeCatalyst or read the documentation. We can’t wait to see how you innovate with CodeCatalyst!

The return of ECMAScript 2023 (and Angular)

#​634 — April 13, 2023

Read on the Web

JavaScript Weekly

The JavaScript Equality Table GameMinesweeper will feel like a walk in the park after this reminder of the horrors of JavaScript’s ==. If you need to go in depth, Section 7.2.14 of the ECMAScript spec will help, but otherwise? Stick to three equals (===) unless you have a good reason not to.

Reinis Ivanovs

htmx 1.9 Released — htmx (homepage) is an increasingly popular library outside of the JavaScript space as it lets folks use things like WebSockets, SSE, AJAX, and CSS transitions by marking up HTML rather than writing lots of JavaScript. v1.9 adds support for view transitions and generalized inline event handling. The code examples are worth a look – htmx makes a lot possible, with rather little tooling or markup needed.

htmx team

Supercharge AWS S3 Video Streaming with ImageKit’s Video API — Get adaptive bitrate streaming, video optimizations, format conversions, and real-time transformations and watermarking by attaching ImageKit with your AWS S3 bucket.

ImageKit sponsor

The ECMAScript® 2023 Language Spec Steps Forward — After prematurely announcing the progression of the ES2023 spec in February, we can now announce: TC39 has approved the ECMAScript 2023 spec, and while it remains a candidate, it’s now a step closer to eventual ECMA General Assembly approval. The finished proposals list for 2023 now includes Array find from last, hashbang support, Symbols as WeakMap keys, and change Array by copy.

ECMA International

IN BRIEF:

▶️ Angular is back with a vengeance, says Fireship.

Serverless platform AWS Lambda has introduced response streaming on its JS runtime (for now) so you can send response data as it becomes available rather than all at once. (→ Via Serverless Status)

/[]/ A look at a seemingly JS-specific quirk in regular expressions when empty character classes are used.

An analysis of languages used in GitHub pull requests shows JavaScript/TypeScript leading the way with Python just slightly behind. The comments went in lots of odd directions here.

Seven folks at Vue Amsterdam 2023 shared their ▶️ tips on getting started with Vue.js.

▶️ An hour-long chat on the State of Node.js with some leading figures.

Node v18.16.0 (LTS) has been released with backported support for compiling JavaScript code into a single executable app. Node 19’s Ada URL parser also appears.

A striking visual introduction to React and its fundamental concepts.

RELEASES:

Node.js v19.9 (Current)

Puppeteer v19.9 – It’s the week for almost 20s.

pnpm 8.2 – Efficient npm alternative.

Redwood 4.5 – Popular app framework.

Storybook 7.0 – With an official release post this time.

???? Articles & Tutorials

Ranger: Use a Range-Like Syntax for Anything? — const numbers = 1[[…8]], anyone? This is a neat trick for a bit of syntatic sugar, but I’m not sure it would pass the sniff test for most teams. You might find the implementation interesting to check out though. Long may this sort of experimentation continue.

Jon Randy

???? A proposal for JavaScript to get built-in range support is at stage 2.

????  Build and Deploy ‘23: May 3rd – Save the Date! — The ultimate CI/CD virtual conference – best practices and end-user success stories from DevOps experts. Plus, a keynote from Emily Freeman, author of DevOps for Dummies.

Codefresh sponsor

Trying Node’s Built-In Test Runner — In 2022, Node gained an experimental built-in test runner (node:test). It’s going to become stable in the forthcoming Node v20, so it’s a good time to look at how it works and how it compares to other solutions you might already be using.

Gleb Bahmutov

▶  The Right Way To Merge JavaScript Objects — In just one minute, too.

Jack Herrington

Ref vs. Reactive: What to Choose When Using Vue 3 Composition API?

Michael Hoffmann

How to Stream File Uploads to S3 Object Storage from Node.js

Austin Gil

How to Contribute to a Project You Have No Idea About

Michal Warda

???? Code & Tools

Reveal.js 4.5: An HTML Presentation Framework — Brings elegant presentations to anyone with a Web browser. v4.5 was just released with support for jumping to specific slides, a few new themes, and with live reload working with files in subfolders.

Hakim El Hattab

List.js: Add Search, Sort, Filters, and More to Tables and Lists — A handy library for adding search, sort, filters and flexibility to tables, lists or other HTML elements. Want an example? Why, of course.

Jonny Strömberg

????Quokka.js – #1 JavaScript Scratchpad for VS Code — With 2M+ downloads, Quokka.js is the #1 tool for exploring and testing JavaScript/TypeScript. Code runs immediately as you type.

Wallaby.js sponsor

Queue: Async Function Queue with Adjustable Concurrency — Exports a class Queue that implements most of the Array API.

Jesse Tane

Yet Another React Lightbox — Add a lightbox component to your projects “in minutes” – there are several examples to try, as well as a playground with adjustable settings. GitHub repo.

Igor Danchenko

Sandpack 2.6: Component Toolkit for Creating Live Code Editing Experiences — Created by the folks at CodeSandbox, so they surely know what they’re doing in this space. GitHub repo.

CodeSandbox

Easy to Use, Full-Stack Application Monitoring

TelemetryHub sponsor

TS Writer: A Template String Template Engine for Generating Code at Runtime — Rather niche, but aimed at situations where you might need to generate code at runtime in TypeScript.

tinylibs

Minimatch 9.0
↳ Glob matcher library.
     minimatch(“bar.foo”, “*.foo”)

hls.js 1.4
↳ Play HLS in browsers with support for MSE.

Partytown 0.8
↳ Relocate third-party scripts off the main thread.

Plasmo 0.68
“It’s like Next.js for browser extensions”

Obsidian 8.0 – GraphQL, built for Deno.

MUI X 6.1 – React component suite.

TestCafe 2.5 – Automate end-to-end web testing.

Maquette 3.6 – Lightweight virtual DOM library.

Venom 5.0 – WhatsApp bot library.

???? Jobs

Find JavaScript Jobs with Hired — Hired makes job hunting easy-instead of chasing recruiters, companies approach you with salary details up front. Create a free profile now.

Hired

Full Stack JavaScript Engineer @ Emerging Cybersecurity Startup — Small team/big results. Fun + flexible + always interesting. Come build our award-winning, all-in-one cybersecurity platform.

Defendify

????‍???? Got a job listing to share? Here’s how.

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Unit Testing AWS Lambda with Python and Mock AWS Services

When building serverless event-driven applications using AWS Lambda, it is best practice to validate individual components.  Unit testing can quickly identify and isolate issues in AWS Lambda function code.  The techniques outlined in this blog demonstrates unit test techniques for Python-based AWS Lambda functions and interactions with AWS Services.

The full code for this blog is available in the GitHub project as a demonstrative example.

Example use case

Let’s consider unit testing a serverless application which provides an API endpoint to generate a document.  When the API endpoint is called with a customer identifier and document type, the Lambda function retrieves the customer’s name from DynamoDB, then retrieves the document text from DynamoDB for the given document type, finally generating and writing the resulting document to S3.

Figure 1. Example application architecture

Amazon API Gateway provides an endpoint to request the generation of a document for a given customer.  A document type and customer identifier are provided in this API call.
The endpoint invokes an AWS Lambda function that generates a document using the customer identifier and the document type provided.
An Amazon DynamoDB table stores the contents of the documents and the users name, which are retrieved by the Lambda function.
The resulting text document is stored to Amazon S3.

Our testing goal is to determine if an isolated “unit” of code works as intended. In this blog, we will be writing tests to provide confidence that the logic written in the above AWS Lambda function behaves as we expect. We will mock the service integrations to Amazon DynamoDB and S3 to isolate and focus our tests on the Lambda function code, and not on the behavior of the AWS Services.

Define the AWS Service resources in the Lambda function

Before writing our first unit test, let’s look at the Lambda function that contains the behavior we wish to test.  The full code for the Lambda function is available in the GitHub repository as src/sample_lambda/app.py.

As part of our Best practices for working AWS Lambda functions, we recommend initializing AWS service resource connections outside of the handler function and in the global scope.  Additionally, we can retrieve any relevant environment variables in the global scope so that subsequent invocations of the Lambda function do not repeatedly need to retrieve them.  For organization, we can put the resource and variables in a dictionary:

_LAMBDA_DYNAMODB_RESOURCE = { “resource” : resource(‘dynamodb’),
“table_name” : environ.get(“DYNAMODB_TABLE_NAME”,”NONE”) }

However, globally scoped code and global variables are challenging to test in Python, as global statements are executed on import, and outside of the controlled test flow.  To facilitate testing, we define classes for supporting AWS resource connections that we can override (patch) during testing.  These classes will accept a dictionary containing the boto3 resource and relevant environment variables.

For example, we create a DynamoDB resource class with a parameter “boto3_dynamodb_resource” that accepts a boto3 resource connected to DynamoDB:

class LambdaDynamoDBClass:
def __init__(self, lambda_dynamodb_resource):
self.resource = lambda_dynamodb_resource[“resource”]
self.table_name = lambda_dynamodb_resource[“table_name”]
self.table = self.resource.Table(self.table_name)

Build the Lambda Handler

The Lambda function handler is the method in the AWS Lambda function code that processes events. When the function is invoked, Lambda runs the handler method. When the handler exits or returns a response, it becomes available to process another event.

To facilitate unit test of the handler function, move as much of logic as possible to other functions that are then called by the Lambda hander entry point.  Also, pass the AWS resource global variables to these subsequent function calls.  This approach enables us to mock and intercept all resources and calls during test.

In our example, the handler references the global variables, and instantiates the resource classes to setup the connections to specific AWS resources.  (We will be able to override and mock these connections during unit test.)

Then the handler calls the create_letter_in_s3 function to perform the steps of creating the document, passing the resource classes.  This downstream function avoids directly referencing the global context or any AWS resource connections directly.

def lambda_handler(event: APIGatewayProxyEvent, context: LambdaContext) -> Dict[str, Any]:

global _LAMBDA_DYNAMODB_RESOURCE
global _LAMBDA_S3_RESOURCE

dynamodb_resource_class = LambdaDynamoDBClass(_LAMBDA_DYNAMODB_RESOURCE)
s3_resource_class = LambdaS3Class(_LAMBDA_S3_RESOURCE)

return create_letter_in_s3(
dynamo_db = dynamodb_resource_class,
s3 = s3_resource_class,
doc_type = event[“pathParameters”][“docType”],
cust_id = event[“pathParameters”][“customerId”])

Unit testing with mock AWS services

Our Lambda function code has now been written and is ready to be tested, let’s take a look at the unit test code!   The full code for the unit test is available in the GitHub repository as tests/unit/src/test_sample_lambda.py.

In production, our Lambda function code will directly access the AWS resources we defined in our function handler; however, in our unit tests we want to isolate our code and replace the AWS resources with simulations.  This isolation facilitates running unit tests in an isolated environment to prevent accidental access to actual cloud resources.

Moto is a python library for Mocking AWS Services that we will be using to simulate AWS resource our tests.  Moto supports many AWS resources, and it allows you to test your code with little or no modification by emulating functionality of these services.

Moto uses decorators to intercept and simulate responses to and from AWS resources.  By adding a decorator for a given AWS service, subsequent calls from the module to that service will be re-directed to the mock.

@moto.mock_dynamodb
@moto.mock_s3

Configure Test Setup and Tear-down

The mocked AWS resources will be used during the unit test suite.  Using the setUp() method allows you to define and configure the mocked global AWS Resources before the tests are run.

We define the test class and a setUp() method and initialize the mock AWS resource.  This includes configuring the resource to prepare it for testing, such as defining a mock DynamoDB table or creating a mock S3 Bucket.

class TestSampleLambda(TestCase):
def setUp(self) -> None:
dynamodb = boto3.resource(“dynamodb”, region_name=”us-east-1″)
dynamodb.create_table(
TableName = self.test_ddb_table_name,
KeySchema = [{“AttributeName”: “PK”, “KeyType”: “HASH”}],
AttributeDefinitions = [{“AttributeName”: “PK”,
“AttributeType”: “S”}],
BillingMode = ‘PAY_PER_REQUEST’

s3_client = boto3.client(‘s3’, region_name=”us-east-1″)
s3_client.create_bucket(Bucket = self.test_s3_bucket_name )

After creating the mocked resources, the setup function creates resource class object referencing those mocked resources, which will be used during testing.

mocked_dynamodb_resource = resource(“dynamodb”)
mocked_s3_resource = resource(“s3”)
mocked_dynamodb_resource = { “resource” : resource(‘dynamodb’),
“table_name” : self.test_ddb_table_name }
mocked_s3_resource = { “resource” : resource(‘s3’),
“bucket_name” : self.test_s3_bucket_name }
self.mocked_dynamodb_class = LambdaDynamoDBClass(mocked_dynamodb_resource)
self.mocked_s3_class = LambdaS3Class(mocked_s3_resource)

Test #1: Verify the code writes the document to S3

Our first test will validate our Lambda function writes the customer letter to an S3 bucket in the correct manner.  We will follow the standard test format of arrange, act, assert when writing this unit test.

Arrange the data we need in the DynamoDB table:

def test_create_letter_in_s3(self) -> None:

self.mocked_dynamodb_class.table.put_item(Item={“PK”:”D#UnitTestDoc”,
“data”:”Unit Test Doc Corpi”})
self.mocked_dynamodb_class.table.put_item(Item={“PK”:”C#UnitTestCust”,
“data”:”Unit Test Customer”})

Act by calling the create_letter_in_s3 function.  During these act calls, the test passes the AWS resources as created in the setUp().

test_return_value = create_letter_in_s3(
dynamo_db = self.mocked_dynamodb_class,
s3=self.mocked_s3_class,
doc_type = “UnitTestDoc”,
cust_id = “UnitTestCust”
)

Assert by reading the data written to the mock S3 bucket, and testing conformity to what we are expecting:

bucket_key = “UnitTestCust/UnitTestDoc.txt”
body = self.mocked_s3_class.bucket.Object(bucket_key).get()[‘Body’].read()

self.assertEqual(test_return_value[“statusCode”], 200)
self.assertIn(“UnitTestCust/UnitTestDoc.txt”, test_return_value[“body”])
self.assertEqual(body.decode(‘ascii’),”Dear Unit Test Customer;nUnit Test Doc Corpi”)

Tests #2 and #3: Data not found error conditions

We can also test error conditions and handling, such as keys not found in the database.  For example, if a customer identifier is submitted, but does not exist in the database lookup, does the logic handle this and return a “Not Found” code of 404?

To test this in test #2, we add data to the mocked DynamoDB table, but then submit a customer identifier that is not in the database.

This test, and a similar test #3 for “Document Types not found”, are implemented in the example test code on GitHub.

Test #4: Validate the handler interface

As the application logic resides in independently tested functions, the Lambda handler function provides only interface validation and function call orchestration.  Therefore, the test for the handler validates that the event is parsed correctly, any functions are invoked as expected, and the return value is passed back.

To emulate the global resource variables and other functions, patch both the global resource classes and logic functions.

@patch(“src.sample_lambda.app.LambdaDynamoDBClass”)
@patch(“src.sample_lambda.app.LambdaS3Class”)
@patch(“src.sample_lambda.app.create_letter_in_s3”)
def test_lambda_handler_valid_event_returns_200(self,
patch_create_letter_in_s3 : MagicMock,
patch_lambda_s3_class : MagicMock,
patch_lambda_dynamodb_class : MagicMock
):

Arrange for the test by setting return values for the patched objects.

patch_lambda_dynamodb_class.return_value = self.mocked_dynamodb_class
patch_lambda_s3_class.return_value = self.mocked_s3_class

return_value_200 = {“statusCode” : 200, “body”:”OK”}
patch_create_letter_in_s3.return_value = return_value_200

We need to provide event data when invoking the Lambda handler.  A good practice is to save test events as separate JSON files, rather than placing them inline as code. In the example project, test events are located in the folder “tests/events/”. During test execution, the event object is created from the JSON file using the utility function named load_sample_event_from_file.

test_event = self.load_sample_event_from_file(“sampleEvent1”)

Act by calling the lambda_handler function.

test_return_value = lambda_handler(event=test_event, context=None)

Assert by ensuring the create_letter_in_s3 function is called with the expected parameters based on the event, and a create_letter_in_s3 function return value is passed back to the caller.  In our example, this value is simply passed with no alterations.

patch_create_letter_in_s3.assert_called_once_with(
dynamo_db=self.mocked_dynamodb_class,
s3=self.mocked_s3_class,
doc_type=test_event[“pathParameters”][“docType”],
cust_id=test_event[“pathParameters”][“customerId”])

self.assertEqual(test_return_value, return_value_200)

Tear Down

The tearDown() method is called immediately after the test method has been run and the result is recorded.  In our example tearDown() method, we clean up any data or state created so the next test won’t be impacted.

Running the unit tests

The unittest Unit testing framework can be run using the Python pytest utility.  To ensure network isolation and verify the unit tests are not accidently connecting to AWS resources, the pytest-socket project provides the ability to disable network communication during a test.

pytest -v –disable-socket -s tests/unit/src/

The pytest command results in a PASSED or FAILED status for each test.  A PASSED status verifies that your unit tests, as written, did not encounter errors or issues,

Conclusion

Unit testing is a software development process in which different parts of an application, called units, are individually and independently tested. Tests validate the quality of the code and confirm that it functions as expected. Other developers can gain familiarity with your code base by consulting the tests. Unit tests reduce future refactoring time, help engineers get up to speed on your code base more quickly, and provide confidence in the expected behaviour.

We’ve seen in this blog how to unit test AWS Lambda functions and mock AWS Services to isolate and test individual logic within our code.

AWS Lambda Powertools for Python has been used in the project to validate hander events.   Powertools provide a suite of utilities for AWS Lambda functions to ease adopting best practices such as tracing, structured logging, custom metrics, idempotency, batching, and more.

Learn more about AWS Lambda testing in our prescriptive test guidance, and find additional test examples on GitHub.  For more serverless learning resources, visit Serverless Land.

About the authors:

Tom Romano

Tom Romano is a Solutions Architect for AWS World Wide Public Sector from Tampa, FL, and assists GovTech and EdTech customers as they create new solutions that are cloud-native, event driven, and serverless. He is an enthusiastic Python programmer for both application development and data analytics. In his free time, Tom flies remote control model airplanes and enjoys vacationing with his family around Florida and the Caribbean.

Kevin Hakanson

Kevin Hakanson is a Sr. Solutions Architect for AWS World Wide Public Sector based in Minnesota. He works with EdTech and GovTech customers to ideate, design, validate, and launch products using cloud-native technologies and modern development practices. When not staring at a computer screen, he is probably staring at another screen, either watching TV or playing video games with his family.

jQuery 3.6.4 Released: Selector Forgiveness

If you’ve been following along with recent jQuery releases, we have been working on how to address the recent addition of some new selectors in browsers, especially :has. jQuery 3.6.3 settled on the strategy of using native CSS.supports to determined whether a selector should be passed directly to querySelectorAll or instead go through jQuery’s selector engine, as might be the case when using jQuery selector extensions, complex :not(), or other selectors that are valid in jQuery but not in the browser. That all technically worked fine, but came with a downside. Fortunately for us, the fix is no longer necessary and we can go back to the old way. More on that below.

As usual, the release is available on our cdn and the npm package manager. Other third party CDNs will probably have it soon as well, but remember that we don’t control their release schedules and they will need some time. Here are the highlights for jQuery 3.6.4.

The Difference Between What Is Right and What Is Allowed

Whenever you use a selector in CSS, or JS, there is more than one spec involved. There’s a spec to determine whether a selector is valid (i.e. Selectors) and there’s a spec to guide implementers in how a selector should be parsed (i.e. the parser algorithm for consuming a simple block). The parser implementation is more forgiving than the selector spec itself, to allow for things like attribute selectors missing the last ] character.

When we addressed an issue with some selectors that were being added to modern browsers—specifically :has—we started making use of another API available in most of our supported browsers—CSS.supports—to determine whether a selector could safely be passed to native querySelectorAll or whether it needed to go through jQuery’s selector engine. Selectors may need to bypass qSA for multiple reasons. It may be a jQuery-only selector extension (:contains), a standard selector that jQuery supports in a more robust way (:not(complex)), or a selector we know to be buggy sometimes (:enabled or :disabled). Whatever the reason, the introduction of “forgiving parsing” in selectors like :has made our previous way of determining that an issue because the browser would no longer throw errors for some truly invalid selectors. For instance, :has(:contains) no longer threw an error when passed to querySelectorAll. Neither did :has(:monkey) for that matter. CSS.supports seemed to be the answer.

And yet, every solution can have a trade-off. The problem now was that selectors that were technically invalid according to the Selectors spec were throwing errors. But these same selectors used to work fine because the parsers were more, for lack of a better term, forgiving. Essentially, CSS.supports is not as forgiving as the parser.

Meanwhile, in our discussions with spec writers and vendors, it was agreed that we needed to prevent issues similar to the one with :has from happening again in the future. What does that mean? It means we can go back to the old way . . . mostly. While the spec has been updated, browsers will need some time to update their implementations. And because of that, we still recommend upgrading jQuery to the latest version.

Upgrading

We do not expect compatibility issues when upgrading from a jQuery 3.0+ version. To upgrade, have a look at the new 3.5 Upgrade Guide. If you haven’t yet upgraded to jQuery 3+, first have a look at the 3.0 Upgrade Guide.

The jQuery Migrate plugin will help you to identify compatibility issues in your code. Please try out this new release and let us know about any issues you experienced.

If you can’t yet upgrade to 3.5+, Daniel Ruf has kindly provided patches for previous jQuery versions.

Download

You can get the files from the jQuery CDN, or link to them directly:

https://code.jquery.com/jquery-3.6.4.js

https://code.jquery.com/jquery-3.6.4.min.js

You can also get this release from npm:

npm install [email protected]

Slim build

Sometimes you don’t need ajax, or you prefer to use one of the many standalone libraries that focus on ajax requests. And often it is simpler to use a combination of CSS and class manipulation for web animations. Along with the regular version of jQuery that includes the ajax and effects modules, we’ve released a “slim” version that excludes these modules. The size of jQuery is very rarely a load performance concern these days, but the slim build is about 6k gzipped bytes smaller than the regular version. These files are also available in the npm package and on the CDN:

https://code.jquery.com/jquery-3.6.4.slim.js

https://code.jquery.com/jquery-3.6.4.slim.min.js

These updates are already available as the current versions on npm and Bower. Information on all the ways to get jQuery is available at https://jquery.com/download/. Public CDNs receive their copies today, please give them a few days to post the files. If you’re anxious to get a quick start, use the files on our CDN until they have a chance to update.

Thanks

Thank you to all of you who participated in this release by submitting patches, reporting bugs, or testing, including Michal Golebiowski-Owczarek and the whole jQuery team.

We’re on Mastodon!

jQuery now has its very own Mastodon account. We will be cross posting to both Twitter and Mastodon from now on. Also, you may be interested in following some of our team members that have Mastodon accounts.

jQuery: https://social.lfx.dev/@jquery

mgol: https://hachyderm.io/@mgol

timmywil: https://hachyderm.io/@timmywil

Changelog

Full changelog: 3.6.4

Build

Update Sizzle from 2.3.9 to 2.3.10 (#5194, dbe09e39)
Updating the 3.6-stable version to 3.6.4-pre. (a0d68b84)

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Astro 2.0 and TypeScript 5.0 beta

#​623 — January 27, 2023

Read on the Web

JavaScript Weekly

Astro 2.0: The Next-Gen ‘Islands’-Oriented Web Framework — 2.0 includes hybrid rendering (mixing of SSR and SSG outputs), type safety for Markdown & MDX, and an upgrade to Vite 4.0. Astro is worth exploring when performance is key as it works with popular frameworks but lets you deliver the least JS possible to get pages rendered.

Fred Schott

Prefer a talk? Nate Moore’s ViteConf talk ▶️ Islands Architecture, Astro, and You will bring you up to speed.

Deep Cloning Objects in JavaScript, The Modern Way — If you’ve been leaning on something like Lodash for deep cloning, you might not need to any longer. “It’s been a long time coming, but we finally now have the built-in structuredClone function to make deep cloning objects in JavaScript a breeze.”

Steve Sewell

Go From Professional Web Developer to Lead Engineer — Aspiring lead developer? Our collection of comprehensive video courses cover the fundamentals of JavaScript, TypeScript, React, web performance, and more.

Frontend Masters sponsor

Announcing TypeScript 5.0 Beta — A new major version number, but users of the popular typed JS superset will face a ‘similar upgrade experience’ to previously. Decorators make it in as a first class feature, significant performance and package size optimizations are present, export type * is supported, all enums are now union enums, and much more.

Daniel Rosenwasser (Microsoft)

AlaSQL.js 3.0: Isomorphic JavaScript SQL Database — A SQL database you can use in the browser, Node.js or mobile apps. An interesting bit of functionality is you can use SQL to query JavaScript objects – example. “The library adds the comfort of a full database engine to your JavaScript app. No, really.”

Andrey Gershun

IN BRIEF:

? If you’re really into Vue.js, you’ll soon be able to become officially certified in it.

If you’re using React, you should be using a React framework, ? says Andrew Clark of the core team.

The creator of alternative JS runtime Bun asks: “If there’s one thing missing from Bun for you to switch, what is it?” You can reply on Twitter.

jQAPI.com is an amazing meeting of old and new JavaScript – it’s an Astro powered version of jQuery’s documentation!

RELEASES:

Shoelace 2.0
↳ Agnostic library of web components.

μFuzzy 1.0
↳ Tiny fuzzy search library.

React Router 6.8

Node.js 19.5.0

? Articles & Tutorials

Getting Started with SvelteKit — SvelteKit only recently hit 1.0 and this is a comprehensive overview of how to build a site using the Svelte-oriented app framework. It covers topics like routing, layouts, data, props and more.

Adam Rackis

Using .NET Code from JavaScript using WebAssembly“Starting with .NET 7, you can easily run any .NET method from JavaScript without needing the whole Blazor framework.”

Gérald Barré

JavaScript Scratchpad for VS Code (2m+ Downloads) — Quokka.js is the #1 tool for exploring/testing JavaScript with edit-continue experience to see realtime execution and runtime values.

Wallaby.js sponsor

scrollend: A New JavaScript Event — Finally an event you won’t need a hotel booking for. scrollend provides a new way to detect that a scrolling operation is complete in the browser. Is it another Chrome-only nicety? Surprisingly not – Firefox 109+ supports it too.

Adam Argyle (Chrome Team)

Packaging Rust Apps for the npm Registry — Isn’t npm just for JavaScript projects? Nope. Node is required to make this technique work, but as long as you can package and execute a binary, you’re good to go.

Orhun Parmaksız

Making Sense of TypeScript using Set Theory — This article certainly doesn’t hang around. Neat diagrams too.

Vladimir Klepov

React Authentication, Simplified

Userfront sponsor

Accessible Hamburger Buttons without JavaScript — Sometimes you need to consider if modern techniques allow you to avoid JavaScript. Here’s a CodePen if you want to play.

Pausly

While we’re on the topic of less JavaScript, the latest episode of the Stack Overflow podcast ▶️ ‘The less JavaScript, the better’ focuses on Astro.

? Code & Tools

Uppy 3.4: Powerful, Modular JavaScript File Uploader — Upload not just from local sources but even Dropbox or Instagram. Integrates with popular frameworks and supports resumable uploads. GitHub repo.

Transloadit

Nut.js 3.0: Desktop Automation from Node — Take control of your desktop (Windows, macOS or Linux) in code with control over keyboard + pointer, along with image matching functionality. GitHub repo.

Simon Hofmann

Optimize Your Systems’ Performance With TelemetryHub – Real-Time Data Monitoring & Analysis — An advanced data visualization and analysis tool that can help you identify and resolve unseen issues in your environment. Try free.

TelemetryHub by Scout sponsor

Eleventy v2.0: First Beta of the Popular Site GeneratorEleventy is a popular Node.js static site generator and v2.0 includes enough major changes that a thorough beta is needed. The creator ▶️ made this quick video about the release.

Zach Leatherman

Mock Service Worker 1.0: API Mocking Library for Browser and Node — Intercepts requests which you can then mock. Capture outgoing requests using an Express-like routing syntax, complete with parameters, wildcards, and regexes. GitHub repo.

Artem Zakharchenko

Drift: A Self-Hostable Gist-Like / Pastebin Service — Built with Next.js 13.

Max Leiter

Dygraphs 2.2
↳ Interactive charts of time series data.

actions/github-script 6.4
↳ Write GitHub Actions workflows in JS.

Playwright 1.30
↳ Browser automation framework.

Faast.js 6.4
↳ Serverlessly call JS functions on AWS Lambda & Google Cloud Functions.

Cypress 12.4
↳ Testing framework for anything in a browser.

D3plus 2.1
↳ Extend D3.js with more visualization types.

? Jobs

Developer Relations Manager — Join the CKEditor team to build community around an Open Source project used by millions of users around the world ?

CKEditor

Senior Full-Stack Engineer – React + TypeScript — Come help Qwire modernize how studios, composers, artists, publishers, labels, and the rest of the industry manage music rights.

Qwire

Find JavaScript Jobs with Hired — Create a profile on Hired to connect with hiring managers at growing startups and Fortune 500 companies. It’s free for job-seekers.

Hired

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A new jQuery release for Xmas

#​619 — December 16, 2022

Read on the Web

? This is the final issue of the year – we’ll be back on January 6, 2023. We hope you have a fantastic holiday season, whether or not you are celebrating, and we’ll see you for a look back at 2022 in the first week of January 🙂
__
Peter Cooper and the Cooperpress team

JavaScript Weekly

Announcing SvelteKit 1.0Svelte is a virtual DOM-free, compiled ahead of time, frontend UI framework with many fans. SvelteKit introduces a framework and tooling around Svelte to build complete webapps. This release post explains some of its approach and how it differs to other systems.

The Svelte Team

Dr. Axel Tackles Two Proposals: Iterator Helpers and Set Methods — Here’s something to get your teeth into! Dr. Axel takes on two promising ECMAScript proposals and breaks down what they’re about and why they’ll (hopefully) become useful to JavaScript developers. The first tackles iterator helpers (new utility methods for working with iterable data) and the second tackles Set methods which will extend ES6’s Set object.

Dr. Axel Rauschmayer

? Retire your Legacy CMS with ButterCMS — ButterCMS is your new content backend. We’re SaaS so we host, maintain, and scale the CMS. Enable your marketing team to update website + app content without needing you. Try the #1 rated SaaS Headless CMS for your JS app today. Free for 30 days.

? ButterCMS sponsor

?  The Best of Node Weekly in 2022 — In this week’s issue of Node Weekly (our Node.js-focused sister newsletter) we looked back at the most popular items of the year, including the Tao of Node, an array of JavaScript testing best practices, and the most popular Node.js frameworks in 2022.

Node Weekly Newsletter

jQuery 3.6.2 Released — Humor me. You might not be using jQuery anymore, but it’s (still) the most widely deployed JavaScript library and it’s fantastic to see it being maintained.

jQuery Foundation

IN BRIEF:

Node 19.3.0 (Current) has been released to bring npm up to v9.2. Breaking changes in v9.x warrant this update and the release post explains the current policy around npm’s ongoing inclusion in Node.

ƛ The Glasgow Haskell Compiler (GHC) has gained a new JavaScript backend meaning the reference Haskell compiler can now emit JavaScript and be used more easily to build front-end apps.

GitHub is rolling out secrets scanning to all public repos for free.

The New Stack reflects on 2022 as a ‘golden year’ for JavaScript and some of the developments we’ve seen. We’ll be doing our own such roundup in the next issue.

RELEASES:

Node.js 16.19.0 (LTS) and 14.21.2 (LTS)

Chart.js 4
↳ Canvas-based chart library. (Samples.)

PouchDB 8.0
↳ CouchDB-inspired syncing database.

SWR 2.0 – React data-fetching library.

? Articles & Tutorials

Why Cypress v12 is a Big Deal — A practical example-led love letter of sorts to how the latest version of the popular Cypress ‘test anything that runs in a browser’ library makes testing frontend apps smoother than before.

Gleb Bahmutov

Five Challenges to Building an Isomorphic JS Library — When it comes to JavaScript, “isomorphic” means code or libraries that run both on client and server runtimes with minimal adaptations.

Nick Fahrenkrog (Doordash)

▶  A Podcast for Candid Chats on Product, Business & Leadership — Join Postlight leaders & guests as they discuss topics like running great meetings & creating solid product launches.

The Postlight Podcast sponsor

Next, Nest, Nuxt… Nust?“This blog post is for everyone looking for their new favorite JavaScript backend framework.” If the names of frameworks are all starting to blur together in your head, this is for you. Marius explains just what systems like Next and Gatsby do and touches on a few differences.

Marius Obert (Twilio)

Calculating the Maximum Diagonal Distance in a Given Collection of GeoJSON Features using Turf.js — This is cool. Turf.js is a geospatial analysis library, by the way.

Piotr Jaworski

Optimize Interaction to Next Paint — How to optimize for the experimental Interaction to Next Paint (INP) metric — a way to assess a page’s overall responsiveness to user interactions.

Jeremy Wagner & Philip Walton (Google)

Need to Upgrade to React 18.2? Don’t Have Time? Our Experts Can Help — Stuck in dependency hell? We’ve been there. Hire our team of experts to upgrade deps, gradually paying off tech debt.

UpgradeJS.com – JavaScript Upgrade Services by OmbuLabs sponsor

How We Configured pnpm and Turborepo for Our Monorepo

Pierre-Louis Mercereau (NHost)

Rendering Emails with Svelte

Gautier Ben Aim

? Code & Tools

Wretch 2.3: A Wrapper Around fetch with an Intuitive Syntax — A long standing, mature library that makes fetch a little more extensible with a fluent API. Check the examples.

Julien Elbaz

SWR 2.0: Improved React Hooks for Data Fetching — The second major release of SWR (Stale-While-Revalidate) includes new mutation APIs, new developer tools, as well as improved support for concurrent rendering.

Ding, Liu, Kobayashi, and Xu

Don’t Let Your Issue Tracker Be a Four-Letter Word. Use Shortcut

Shortcut (formerly Clubhouse.io) sponsor

vanilla-tilt.js 1.8: A Smooth 3D Tilting Effect Library — No dependencies and simple to use and customize. GitHub repo.

Șandor Sergiu

visx: Airbnb’s Low Level Visualization React Components — Bring your own state management, animation library, or CSS-in-JS.. visx can slot into any React setup. Demos.

Airbnb

Scene.js 1.7: A CSS Timeline-Based Animation Library — Plenty of examples on the site. Has components for React, Vue and Svelte.

Daybrush

PortalVue 3.0
↳ Feature-rich portal plugin for Vue 3.

Kea 3.1
↳ Composable state management for React.

jest-puppeteer 6.2
↳ Run tests using Jest + Puppeteer.

NodeBB 2.7 – Node.js based forum software.

Pino 8.8 – Fast JSON-oriented logger.

? Jobs

Software Engineer — Join our “kick ass” team. Our software team operates from 17 countries and we’re always looking for more exceptional engineers.

Stickermule

Developer Relations Manager — Join the CKEditor team to build community around an Open Source project used by millions of users around the world ?

CKEditor

Find JavaScript Jobs with Hired — Create a profile on Hired to connect with hiring managers at growing startups and Fortune 500 companies. It’s free for job-seekers.

Hired

? And one for fun

Snow.js: Add a Snow Effect to a Web Page — Well, it’s that time of the year (in some parts of the world!) If you’re more interested in how the effect is made, it’s inspired by this CodePen example built around some fancy CSS.

Or if you’re a bit more childish, you could always put Fart.js on your site.. ?

Merry Christmas to you all and we’ll see you again in 2023!

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jQuery 3.6.2 Released!

You probably weren’t expecting another release so soon, but jQuery 3.6.2 has arrived! The main impetus for this release was the introduction of some new selectors in Chrome. More on that below.

As usual, the release is available on our cdn and the npm package manager. Other third party CDNs will probably have it soon as well, but remember that we don’t control their release schedules and they will need some time. Here are the highlights for jQuery 3.6.2.

undefined and whitespace-only CSS variables

jQuery 3.6.1 introduced a minor regression where attempting to retrieve a value for a custom CSS property that didn’t exist (i.e. $elem.css(“–custom”)) threw an error instead of returning undefined. This has been fixed in 3.6.2. Related to that, we also made sure that whitespace-only values return the same thing across all browsers. The spec requires that CSS variable values be trimmed, but browsers are inconsistent in their trimming. We now return undefined for whitespace-only values to make it consistent with older jQuery and across the different browsers.

.contains() with <template>

An issue was recently reported that showed that a <template>‘s document had its documentElement property set to null, in compliance with the spec. While it made sense semantically for a template to not yet be tied to a document, it made for an unusual case, specifically in jQuery.contains() and any methods relying on it. That included manipulation and selector methods. Fortunately, the fix was simple.

It wasn’t Ralph that broke the internet

The internet experienced a bit of a rumble when Chrome recently introduced some new selectors, the most pertinent of which being :has(). It was a welcome addition, and one celebrated by the jQuery team, but a change to the spec meant that :has() used what’s called “forgiving parsing”. Essentially, even if the arguments for :has() were invalid, the browser returned no results instead of throwing an error. That was problematic in cases where :has() contained another jQuery selector extension (e.g. :has(:contains(“Item”))) or contained itself (:has(div:has(a))). Sizzle relied on errors like that to know when to trust native querySelectorAll and when to run the selector through Sizzle. Selectors that used to work were broken in all jQuery versions dating back to the earliest jQuery versions.

And yet, this little drama didn’t last long. The Chrome team quickly implemented a workaround to fix previous jQuery versions in the vast majority of cases. Safari handled their implementation of :has() a little differently and didn’t have the same problem. But, there’s still an important issue open to determine how to address this in the CSS spec itself. The CSSWG has since resolved the issue.

jQuery has taken steps to ensure that any forgiving parsing doesn’t break future jQuery versions, even if previous jQuery versions would still be affected.

Upgrading

We do not expect compatibility issues when upgrading from a jQuery 3.0+ version. To upgrade, have a look at the new 3.5 Upgrade Guide. If you haven’t yet upgraded to jQuery 3+, first have a look at the 3.0 Upgrade Guide.

The jQuery Migrate plugin will help you to identify compatibility issues in your code. Please try out this new release and let us know about any issues you experienced.

If you can’t yet upgrade to 3.5+, Daniel Ruf has kindly provided patches for previous jQuery versions.

Download

You can get the files from the jQuery CDN, or link to them directly:

https://code.jquery.com/jquery-3.6.2.js

https://code.jquery.com/jquery-3.6.2.min.js

You can also get this release from npm:

npm install [email protected]

Slim build

Sometimes you don’t need ajax, or you prefer to use one of the many standalone libraries that focus on ajax requests. And often it is simpler to use a combination of CSS and class manipulation for web animations. Along with the regular version of jQuery that includes the ajax and effects modules, we’ve released a “slim” version that excludes these modules. The size of jQuery is very rarely a load performance concern these days, but the slim build is about 6k gzipped bytes smaller than the regular version. These files are also available in the npm package and on the CDN:

https://code.jquery.com/jquery-3.6.2.slim.js

https://code.jquery.com/jquery-3.6.2.slim.min.js

These updates are already available as the current versions on npm and Bower. Information on all the ways to get jQuery is available at https://jquery.com/download/. Public CDNs receive their copies today, please give them a few days to post the files. If you’re anxious to get a quick start, use the files on our CDN until they have a chance to update.

Thanks

Thank you to all of you who participated in this release by submitting patches, reporting bugs, or testing, including sashashura, Anders Kaseorg, Michal Golebiowski-Owczarek, and the whole jQuery team.

Changelog

Full changelog: 3.6.2

CSS

Return undefined for whitespace-only CSS variable values (#5120) (8bea1dec)
Don’t trim whitespace of undefined custom property (#5105, c0db6d70)

Selector

Manipulation: Fix DOM manip within template contents (#5147, 5318e311)
Update Sizzle from 2.3.7 to 2.3.8 (#5147, a1b7ae3b)
Update Sizzle from 2.3.6 to 2.3.7 (#5098, ee0fec05)

Tests

Remove a workaround for a Firefox XML parsing issue (965391ab)
Make Ajax tests pass in iOS 9 (d051e0e3)

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jQuery 3.6.3 Released: A Quick Selector Fix

Last week, we released jQuery 3.6.2. There were several changes in that release, but the most important one addressed an issue with some new selectors introduced in most browsers, like :has(). We wanted to release jQuery 3.6.3 quickly because an issue was reported that revealed a problem with our original fix. More details on that below.

As usual, the release is available on our cdn and the npm package manager. Other third party CDNs will probably have it soon as well, but remember that we don’t control their release schedules and they will need some time. Here are the highlights for jQuery 3.6.3.

Using CSS.supports the right way

After the issue with :has that was fixed in jQuery 3.6.2, we started using CSS.supports( “selector(SELECTOR)”) to determine whether a selector would be valid if passed directly to querySelectorAll. When CSS.supports returned false, jQuery would then fall back to its own selector engine (Sizzle). Apparently, our implementation had a bug. In CSS.supports( “selector(SELECTOR)”), SELECTOR needed to be a <complex-selector> and not a <complex-selector-list>. For example:

CSS.supports(“selector(div)”); // true
CSS.supports(“selector(div, span)”); // false

This meant that all complex selector lists were passed through Sizzle instead of querySelectorAll. That’s not necessarily a problem in most cases, but it does mean that some level 4 selectors that were supported in browsers but not in Sizzle, like :valid, no longer worked if it was part of a selector list (e.g. “input:valid, div”). It should be noted this currently only affects Firefox, but it will be true in all browsers as they roll out changes to CSS.supports.

This has now been fixed in jQuery 3.6.3 and it is the only functional change in this release.

Upgrading

We do not expect compatibility issues when upgrading from a jQuery 3.0+ version. To upgrade, have a look at the new 3.5 Upgrade Guide. If you haven’t yet upgraded to jQuery 3+, first have a look at the 3.0 Upgrade Guide.

The jQuery Migrate plugin will help you to identify compatibility issues in your code. Please try out this new release and let us know about any issues you experienced.

If you can’t yet upgrade to 3.5+, Daniel Ruf has kindly provided patches for previous jQuery versions.

Download

You can get the files from the jQuery CDN, or link to them directly:

https://code.jquery.com/jquery-3.6.3.js

https://code.jquery.com/jquery-3.6.3.min.js

You can also get this release from npm:

npm install [email protected]

Slim build

Sometimes you don’t need ajax, or you prefer to use one of the many standalone libraries that focus on ajax requests. And often it is simpler to use a combination of CSS and class manipulation for web animations. Along with the regular version of jQuery that includes the ajax and effects modules, we’ve released a “slim” version that excludes these modules. The size of jQuery is very rarely a load performance concern these days, but the slim build is about 6k gzipped bytes smaller than the regular version. These files are also available in the npm package and on the CDN:

https://code.jquery.com/jquery-3.6.3.slim.js

https://code.jquery.com/jquery-3.6.3.slim.min.js

These updates are already available as the current versions on npm and Bower. Information on all the ways to get jQuery is available at https://jquery.com/download/. Public CDNs receive their copies today, please give them a few days to post the files. If you’re anxious to get a quick start, use the files on our CDN until they have a chance to update.

Thanks

Thank you to all of you who participated in this release by submitting patches, reporting bugs, or testing, including Michal Golebiowski-Owczarek and the whole jQuery team.

Changelog

Full changelog: 3.6.3

Build

remove stale Insight package from custom builds (81d5bd17)
Updating the 3.x-stable version to 3.6.3-pre. (2c5b47c4)

Selector

Update Sizzle from 2.3.8 to 2.3.9 (#5177, 8989500e)

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Is React a Framework? Software Engineer Answering

By definition – React is one of the most popular JavaScript UI libraries nowadays. It comes in second place after jQuery among all web frameworks! React’s popularity has grown rapidly thanks to a simple and declarative API that allows you to build high-performance applications, and that momentum keeps growing. Still, there is often discussion and questioning that React is a framework or library.

Firstly, let’s look what the differents between framework and library? 

The framework belongs to the main() function. It executes some functions, e.g. controlling a collection of windows on the screen. The framework can, in principle, work even if you have not set it up in any way. It does something, e.g. it places an empty window with default widgets. The framework defines the general nature of the program, and your code provides a specific setting. These settings can be very significant, as both a word processor and a spreadsheet can be created using the same framework.

The library is the set of tools used by your code. Your code belongs to the main() and provides the overall structure of the program. A library performs some specific task, such as sending traffic over a network, drawing charts, or something else. The library can do big things, like draw a view of a three-dimensional space full of objects, but only after you tell it about those objects.

The framework can call your code, which in turn calls the library. But your code never calls the framework, except perhaps for system() or exec() functions.

But, is React a Framework? 

We asked our Software Engineers Team for their opinion and they were split into two parts: some maintain the view that React is a library, and others assign it as a Framework. Here are the most outstanding opinions:

From my point of view, React is not a framework, it’s just a library with no specific requirements for project structure. It’s about describing the abstractions of your application, logic, routing, data exchange, and so on. And React simplifies the work with this data, and optimizes the work with it

Anton M. – Software Engineer at Flatlogic.com

From my point of view, React is not a framework, it’s just a library with no specific requirements for project structure. It’s about describing the abstractions of your application, logic, routing, data exchange, and so on. And React simplifies the work with this data, and optimizes the work with it

I know that react calls itself a “library”, and a lot of developers prefer to react to the home page with the title “library”. However, I think that React is more like a framework now, with different targets like web, react native, etc. And the foundation of React is JSX, which is crucial for proper developer experience, and requires a build step, so you can’t just slap a bunch of JSX files into a browser and call it a day. Nowadays when you say “I built this app with React” you don’t mean that you used it on one page or as a modern jquery alternative. You mean that you built everything around react, with its ecosystem, its best practices, etc. And with all those points in mind, I’d rather call react the framework, than a library

Viktor S. – Staff Engineer at Flatlogic.com

We also conducted the research among others software engineers and would like to share with you the most impressive arguments on this point. 

So, is React a Framework or a Library?

React is a Library

React is a JavaScript library for building user interfaces. It is maintained by Facebook and a community of individual developers and companies. React can be used as a base in the development of single-page or mobile applications.

Now Why Library, not a Framework?

different definitions for library and framework:

a framework is a software where you plug your code into
a library is a software that you plug into your code

In terms of this definition, React is a framework. But some people, especially in the frontend world, say a framework has to bring stuff like routers and/or widgets, etc. 

So Angular, and ExtJS are frameworks, but React isn’t, because it only gives you the means to build components and render them into the DOM.

Let’s make it simple, in React we have to include packages for everything it’s not necessary but yes we can add them, thus React is a Library but if we are not given an option to do so with our code then that’s a framework like Angular and Vue.

React is a library because it’s only supposed to deal with the view part of the eco-system, and you can integrate it easily in any project you’re working on currently, it’s something like jQuery, it only helps you with organizing your views into reusable components, of course, the performance is one of the best things about React, especially with the new Fiber algorithm, things will be faster seeing the scheduler mechanism, unlike Angular, it’s a framework that gives you everything you need, most of the things are already built-in, for React you need to create your own/or grab some modules from npm to add extra functionality as need per your project.

It depends on how you use it. If you’re writing a small program and you structure your program around working with React, you are probably thinking of React as a framework.

If you have a big program and you use React as a small part of it just for handling output, then you’re probably thinking of React as a library.

If your program is 90% user interface, and not only your program structure but your data structures are shaped to fit the React system, then you may even think of React as a language. Hey, if TypeScript can be a language, why not React?

React is a library, cause it has mostly evolved into a vast ecosystem that is barely distinguishable from a framework. A framework protects the edges, whereas a library provides a tool for doing certain tasks. React handles exactly one task: abstracted Web Components. It offers an internal state, lifecycles, and external properties, as well as a renderer for a browser or comparable environment through ReactDOM – and nothing more.

This has a few advantages: it is smaller than a full-featured framework, has fewer opinions on how to address problems, and so provides more options.

I’d say React is a library posing as a framework. It feels like working in a framework (esp. with JSX, though using that is optional), but under the hood, it is just a library. This definition is quite good:

a framework is software that you plug your code into (e.g. you work “inside” it).
a library is software that you plug into your code (e.g. you “hand-off” certain tasks to it, or build “on top” of it).

React feels like the first, but is the second. The attached video compares React and Angular and hints at the distinction. Since React treats your code as a black box, you can push the data-binding concerns out to the edges of your system, to be “handed off” to React (i.e. how you would use a library). Angular, on the other hand, forces you to work “inside” their “scopes” using their “directives” to handle data-binding. In Angular, you are passing your data through scopes that observe your data model. You are always at the mercy of whichever directives they are building into their framework scaffolding. You are also working “inside” HTML (JS-in-HTML), with all the constraints that impose (giving more of a framework feeling). But with React, you have less of that feeling, since you have freedom (full power of JS), and can build “on top” of React (HTML/JSX-in-JS). This is good since JS is inherently more powerful than HTML.

React is a Framework

React is a framework. Honestly caring about the difference between a library and a framework is a bit pedantic, so I’d say you can call it either. Having said that, my definitions of the two words are that a library is a collection of functions, and a framework is a way of doing things.

By this definition, React is a framework because it forces you to build UI in the React way instead of the Angular, etc. On the other hand, the dash is a perfect example of a library because it’s just a collection of functions, use them however you want.

JavaScript is known for its abundance of new plugins, frameworks, and other things created by its massive community of developers and designers.

You must be wondering what this fact has to do with the React JS framework and other frameworks. The truth is that many of the leading IT firms have already embraced JavaScript and leveraged its benefits.

That should answer the question and not cause any other debates, right? Well, not exactly; the debate over Is React a framework or library? is as strong as ever.

Over the years, developers, software engineers, and developer communities came up with pros and cons related to the status of React as a library or React as a framework. Let’s analyze them together.

React as a library

React can be easily swapped by some other javascript library offering similar functionalities.
React can be easily plugged into an existing technology stack – and that’s the definition of a library.

React as a framework

Related libraries must work in an opinionated way.
Because of its state and lifecycle on the components, you inverted the control to React.

Are you asking why React was designed as a library and not a framework [1] or why it is classified as a library and not a framework [2]?

[1] Why it was built that way. A library is something you can add to an existing project to enhance it. It does not impose any restrictions or conventions on your application design and you can supplement it with other libraries of your choice to flesh out your application. There is also a shorter learning curve (usually) on a library as you can add it incrementally to your project. A framework on the other hand implies structure and convention, you need to follow the conventions of the framework. In many cases a framework limits you to working within these conventions – you cannot (or it is difficult) to mix a framework with other code.

There are use cases for each.

[2] Why it is not classified as a framework. Based on the definition of a framework it does not fit the bill – it is a library that is added to your code – it does not impose structure – beyond the use of the library itself and it can be mixed in with other code.

React does not solve any structural or architectural problems on the app level. It provides us with a set of methods for better (in my opinion) handling of the front-end. I remember when jQuery did that back in the day, and how that started the revolution… React is now doing the same, just better.

Because React is a library eventually we got Flux and Redux. Both of them are handling real-world problems that come alongside Scaling. Mare library does not think about that.

React is a framework because Redux is referencing it as one (Source). Ah, as I started to hope that something in life is going to be easy. With React and Redux there is a clear layer of separation between the view and data. That is why React is not a complete framework to solve the entire problem.

Conclusion

Soft engineers spend a lot of time talking about what React is. The answer is important for any React soft engineer, no matter their skill level. That is because it indicates what they should know and how they should work when developing any React application. Depending on who you are, a beginner or an advanced React soft engineer, I hope this thoughtful research will improve your development process as you build your next React project.

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