--- title: "#340: How Long 1MB of JS Takes to Parse on Various Devices" publication: "JavaScript Weekly" issue: 340 published_at: "2017-06-23" canonical_url: "https://javascriptweekly.com/issues/340" --- #340: How Long 1MB of JS Takes to Parse on Various Devices This week's JavaScript news — [Read this e-mail on the Web](http://javascriptweekly.com/issues/340) JavaScript WeeklyIssue 340 — June 23, 2017[Using JavaScript for Microcontroller Development](https://auth0.com/blog/javascript-for-microcontrollers-and-iot-part-1/)Learn about the ecosystem and some options for using JS on microcontrollers and IoT platforms. Sebastián Peyrott [A Spreadsheet in 25 Lines of ES6](http://jsfiddle.net/ondras/o3tzx1px/)A modern ES6 update to a _very_ popular [demo from 2013](http://jsfiddle.net/ondras/hYfN3/) which implemented a working spreadsheet in very few lines of JS. Ondřej Žára [Picking Jest Over Mocha: A Testing Tool Comparison](https://gziolo.pl/2017/06/17/picking-jest-over-mocha/)A developer at Automattic (the company behind WordPress) explains why they prefer Jest to Mocha for JavaScript testing. Grzegorz Ziółkowski [![CircleCI\](https://copm.s3.amazonaws.com/d10327e4.png)](https://circleci.com/?utm_source=cooperpress&utm_medium=newsletter&utm_campaign=june&utm_content=javascript-weekly)[Build Faster. Test More. Fail Less. Easy CI/CD for JavaScript](https://circleci.com/?utm_source=cooperpress&utm_medium=newsletter&utm_campaign=june&utm_content=javascript-weekly)CircleCI’s continuous integration and delivery platform helps software teams rapidly release code with confidence. _NEW RELEASE: Workflows_ - Custom job orchestration provides granular control over your development process. CircleCISponsor [Cell: A Self-Constructing Web App Framework](https://github.com/intercellular/cell)An intriguing new approach to creating a simple front-end app where you write the entire app mostly declaratively in a single JS object. Intercellular [React Express: Learn React with Interactive Examples](http://www.react.express/)An opinionated, all-in-one guide walking through create-react-app, webpack, Babel, ES2015+, JSX, Redux, CSS-in-JS, and more. Devin Abbott [Codemods: A Quick and Easy Way to Automate Code Refactoring](https://www.sitepoint.com/getting-started-with-codemods/)An introduction to the idea of using Facebook’s [jscodeshift](https://github.com/facebook/jscodeshift) to create and apply ‘codemods’ to automate changes to your code. Chris Laughlin [The Parse Times of 1MB of JavaScript on Various Devices](https://twitter.com/HenriHelvetica/status/877924754195324928)Performance isn’t just about how quickly a device can download a huge blob of JavaScript, but how long it takes to parse too. Henri Helvetica and Tim Kadlec Jobs - [Front End Engineer at EDITED (London)](https://edited.com/jobs/engineering/?utm_source=javascriptweekly&utm_medium=email)Join us to impact how the world's biggest retailers operate by making a web app with great UX and DX using React, Redux and Glamor EDITED - [Web Application Engineer - Apple Inc. (California, USA)](https://ars2.equest.com/?response_id=6083dea6bbd0f0f02c35a57b3cfac971)Our Media Products Engineering team is looking for a software engineer to build and enhance our algorithmic quality evaluation tools. Apple Inc. - [Experienced Node Engineer at eBench (Remote)](http://blog.ebench.com/2017/06/were-hiring-experienced-node-engineer.html?utm_source=javascriptweekly&utm_medium=email)We're a SaaS company that creates beautiful data visualizations. Enjoy crafting quality code? We would love to hear from you. EBENCH In Brief [The State of Angular and the Due Date of Version 5](https://hackernoon.com/the-state-of-angular-and-the-due-date-of-version-5-68374002267f) news Dor Moshe [ForwardJS Tickets on sale today](https://forwardjs.com) news Attend full-day hands-on React workshops and dozens of talks at ForwardJS San Francisco this July. ForwardJSSponsor [Creating a Personal Bluetooth Beacon with Puck.js](https://lab.io/articles/2017/06/12/puck-js-beacon/) tutorial Adam Butler [Unambiguous Webpack Config with TypeScript](https://medium.com/@devonmarisa/unambiguous-webpack-config-with-typescript-8519def2cac7) tutorial Devon Marisa Zuegel [The Art of Building a Progressive Web App with Ember](https://madhatted.com/2017/6/16/building-a-progressive-web-app-with-ember) tutorial Matthew Beale [A Thorough (Re)Introduction to Callbacks](https://zellwk.com/blog/callbacks/) tutorial A thorough guide aimed at newbies/learners. Zell Liew [A Brief Guide to Reliable Stream Processing with RxJS](https://hackernoon.com/a-semi-quick-guide-to-reliable-stream-processing-with-rxjs-77cd8cb47f38) tutorial Hendrik Swanepoel [How to Create Interactive JavaScript Charts from Custom Data Sets](https://www.sitepoint.com/javascript-charts-custom-data-sets/) tutorial SitePoint [An Introduction to Sets in JavaScript](https://alligator.io/js/sets-introduction/) tutorial Alligator [Register for M101JS: MongoDB for Node.js Developers](https://university.mongodb.com/courses/M101JS/about?jmp=cpress&utm_campaign=WW_CP_newsletter_sponsorship_FY17Q2&utm_content=sponsored&utm_medium=display&utm_source=javascriptweekly0623) Learn everything you need to know to get started building a MongoDB-based app. MongoDBSponsor [Techniques for Decomposing React Components](https://medium.com/dailyjs/techniques-for-decomposing-react-components-e8a1081ef5da) tutorial David Tang [Introducing Lazy Arrays in JavaScript with lazy-arr](https://performancejs.com/post/ewffd34/Introducing:-Lazy-arrays-in-JavaScript) tutorial PerformanceJS [ES2017's async/await is 'The Best Thing to Ever Happen to JavaScript'](https://certsimple.com/blog/javascript-equals-async-await) opinion Mike MacCana [Functional Programming in JS is an Antipattern](https://medium.com/@alexdixon/functional-programming-in-javascript-is-an-antipattern-58526819f21e) opinion Here’s your thought provoking opinion piece of the week. Alex Dixon [Why One Developer Chose React Over Vue](https://medium.com/@CalinLeafshade/why-i-chose-react-over-vue-3dd9a230b507) opinion He prefers immutability and using JS instead of directives. Steven Poulton [Making the Switch from AngularJS to Angular in an Enterprise Dev Shop](http://developer.telerik.com/topics/web-development/making-switch-angularjs-angular-enterprise-dev-shop/) story Telerik Developer Network [jQuery-contextMenu: A jQuery Context Menu Plugin and Polyfill](https://github.com/swisnl/jQuery-contextMenu) code SWIS [Spected: A Low Level Validation Library for Objects](https://github.com/25th-floor/spected) code 25th-floor GmbH [Tetris Reimplemented with Vue, Vuex, and Immutable.js](https://github.com/Binaryify/vue-tetris/blob/master/README-EN.md) code An interesting implementation that’s [very smooth to play.](http://binaryify.github.io/vue-tetris/) Binaryify [p-iteration: Make Array Iteration Easy with async/await and Promises](https://github.com/toniov/p-iteration) code Antonio V [vue-table-component: A Vue Component to Filter and Sort Tables](https://medium.com/@freekmurze/a-straightforward-vue-component-to-filter-and-sort-tables-22c6b33a2bfb) code Freek Van der Herten [How to find & fix the slowest code in your .NET application with Redgate](http://www.red-gate.com/products/dotnet-development/ants-performance-profiler/?utm_source=javascriptweekly&utm_medium=displayemail&utm_content=slowest_code&utm_campaign=antsperformanceprofiler&utm_term=email-25733) Red GateSponsor Curated by [Peter Cooper](http://twitter.com/peterc) and published by [Cooperpress](https://cooperpress.com/). 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