---
title: "This week's JavaScript news, issue 325"
publication: "JavaScript Weekly"
issue: 325
published_at: "2017-03-09"
canonical_url: "https://javascriptweekly.com/issues/325"
---

This week's JavaScript news, issue 325

This week's JavaScript news — [Read this e-mail on the Web](http://javascriptweekly.com/issues/325)

JavaScript WeeklyIssue 325 — March 9, 2017[Analysing The Use of Outdated JavaScript Libraries](https://blog.acolyer.org/2017/03/07/thou-shalt-not-depend-on-me-analysing-the-use-of-outdated-javascript-libraries-on-the-web/)A thorough summary of a new academic paper that looks at the analysis of JavaScript used across 133,000 different sites. Tim Kadlec of Snyk also [shared some insights](https://snyk.io/blog/known-vulnerabilities-in-javascript/) on its findings. Adrian Colyer 
[eslint-plugin-compat: Lint the Browser Compatability of APIs Used](https://github.com/amilajack/eslint-plugin-compat)For example, specify what browsers and versions you want to support, and it’ll warn you if your code uses unsupported features. Amila Welihinda 
[Franc: Natural Language Detection in Pure JS](https://github.com/wooorm/franc)Uses a library of trigrams that are most popular in up to 375 languages, Franc works in both Node and the browser to detect natural languages used in a text. [Demo here.](http://wooorm.com/franc/) Titus Wormer 
[![Rollbar\](https://copm.s3.amazonaws.com/9562629a.png)](https://rollbar.com/jsweekly?utm_source=javascriptweekly&utm_medium=email)[Using JavaScript Source Maps to Debug Errors, Better 👀](https://rollbar.com/jsweekly)Let's explore JavaScript source maps together, starting with the basics. What are they? How to enable them? Why aren't they working? [Learn more.](https://rollbar.com/jsweekly) RollbarSponsor
[Polymer 2.0 Release Candidate Released](https://www.polymer-project.org/blog/2017-03-08-2-0-rc)Now considered feature complete, Polymer 2.0 is ready to test and try. A key focus has been on improved interoperability with other libraries and frameworks. Dan Freedman 
[FPO: Functional Programming (FP) By Any Other Name](https://davidwalsh.name/functional-programming)Kyle Simpson introduces [FPO](https://github.com/getify/FPO), a JavaScript library for functional programming that supports named-argument style methods. Kyle Simpson 
[Lets Define My Favorite JavaScript Test](https://bocoup.com/blog/my-favorite-javascript-test)No, the title isn’t missing an apostrophe - Mike’s favorite test in Test262, the official test suite for ECMAScript, is _really_ `let` twice. Intrigued? Mike Pennisi 
[How V8 Made for...in Fast](https://v8project.blogspot.com/2017/03/fast-for-in-in-v8.html)A _very_ technical and thorough look at how V8 has made ‘for in’ faster than ever. Camillo Bruni 
[WebAssembly: Under The Hood with Mozilla](https://www.youtube.com/watch?v=o52_5qAJhNg)In just 7 minutes, Alon Zakai, originally the creator of the [Emscripten](https://github.com/kripken/emscripten) LLVM-to-JavaScript compiler, explains what WebAssembly is all about. YouTube 
[Three Ways of Understanding Promises](http://www.2ality.com/2016/10/understanding-promises.html)Dr. Axel tackles promises in a very quick, straightforward way. Dr. Axel Rauschmayer 


Jobs

- [Node.js Developer at X-Team (Remote)](https://x-team.com/nodejs-developer/?utm_source=newsletter&utm_medium=email&utm_campaign=javascript-march-9-17)We're looking for a developer with an extensive knowledge of Node.js and Javascript. We are 100% remote and we provide the funding needed to help you achieve your goals and grow. X-Team
- [Sr. JavaScript / Ruby Developer](https://www.stickermule.com/jobs?job=714da6cc-dc8b-4453-8bd6-7b0fa41ebd37&title=sr-javascript--ruby-developer)Sticker Mule is looking for passionate engineers to join our remote team. Come help us build the best e-commerce experience using Ruby, Rails, React, Node, Docker and more. Sticker Mule
- [Senior Front-End Developer at Catawiki (Amsterdam or Assen)](https://www.catawiki.com/jobs/job/senior-front-end-developer?gh_jid=547807)Our mission is to make special items available to everyone. We offer a unique opportunity to join our team and improve the experience for millions of our users with an iterative, small-step approach through A/B testing. Catawiki

In Brief

[Marko 4.0 Released: eBay's Component Based UI Library](https://medium.com/@mlrawlings/marko-4-0-is-here-837884c5f60d) news
Michael Rawlings

[Testing Routes in Angular 2](https://semaphoreci.com/community/tutorials/testing-routes-in-angular-2) tutorial
Matt Fehskens

[10 Practical Use Cases for ES6 Proxies](http://dealwithjs.io/es6-features-10-use-cases-for-proxy/) tutorial
Csaba Hellinger

[Refactoring Legacy JavaScript Code to Use Classes: The Good, Bad and Ugly](https://arxiv.org/abs/1703.01690) 
An academic paper.
Silva, Valente, Bergel

[Workshop: Brian Lonsdorf's Practically Functional Programming](https://forwardcourses.com/workshops/28) course 
Master monoids, monads and other algebraic abstractions to produce highly composable, safer, and simpler code.
Forward CoursesSponsor

[An 11 Minute Introduction to Angular CLI](https://www.youtube.com/watch?v=IQwXaZbdZH8) video
YouTube

[Previewing Mozilla's WebAssembly Explorer](https://hacks.mozilla.org/2017/03/previewing-the-webassembly-explorer/) video 
A look at a new tool to help developers understand and experiment with WebAssembly.
Mozilla

[Ace JavaScript Interviews: Scoping And Hoisting](https://pusher.com/sessions/meetup/london-node-user-group/ace-javascript-interviews-scoping-and-hoisting) video
Fox Reymann

[Pinterest's Utilities for Creating and Testing Service Workers](https://github.com/pinterest/service-workers) tools
Pinterest

[A Jest Cheat Sheet](https://github.com/sapegin/jest-cheat-sheet/blob/master/Readme.md) tools
Artem Sapegin

[Awesome Grid: A Curated List of Grid/Table Libraries](https://github.com/FancyGrid/awesome-grid) tools

[Depercolator: Tool for Converting CoffeeScript to Idiomatic JS and JSX](https://github.com/bugsnag/depercolator) tools
Bugsnag

[React InstantSearch⚡ Lightning fast search for web and native apps](https://community.algolia.com/instantsearch.js/react/?utm_source=javascript-weekly&utm_campaign=react-is&utm_medium=email) tools 
Algolia provides UI widgets and connectors (HOC) so you can build instant search in a few lines of code.
AlgoliaSponsor

[blurify.js: Image Blurring from JavaScript](https://github.com/JustClear/blurify) code

[react2angular: Embed React Components in Angular 1 Apps](https://github.com/coatue/react2angular) code
Coatue

[Angular Gauge: Customizable Gauge Directive for Angular Apps](https://ashish-chopra.github.io/angular-gauge/) code
Ashish Chopra

[Element: A Vue 2.0 Based Component Library/UI Toolkit](http://element.eleme.io/) code

[HyperApp: 1KB JavaScript Library for Building Modern UI Applications](https://github.com/hyperapp/hyperapp) code
Jorge Bucaran

[webpack-blocks: Configure Webpack using Functional Feature Blocks](https://github.com/andywer/webpack-blocks) code
Andy Wermke

Curated by [Peter Cooper](http://twitter.com/peterc) and published by [Cooperpress](https://cooperpress.com/).

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