FastImage, performant React Native image component

React Native’s Image component handles image caching like browsers for the most part. If the server is returning proper cache control headers for images you’ll generally get the sort of built in caching behavior you’d have in a browser. Even so many people have noticed: Flickering. Cache misses. Low performance loading from cache. Low performance […]

A Tinder Progressive Web App Performance Case Study

Addy Osmani: Tinder recently swiped right on the web. Their new responsive Progressive Web App — Tinder Online — is available to 100% of users on desktop and mobile, employing techniques for JavaScript performance optimization, Service Workers for network resilience and Push Notifications for chat engagement. Today we’ll walk through some of their web perf learnings. Their PWA is […]

Implement FLIP transitions easily with flipping

Back in 2015 Paul Lewis published a brilliant article named FLIP your animations, a technique to getting smooth animations on the web. FLIP stands for First, Last, Invert, Play First: before anything happens, record the current (i.e., first) position and dimensions of the element that will transition. You can use element.getBoundingClientRect() for this, as will […]

XCode 9.0: Fixing a Slow/Unresponsive iOS Simulator

Whilst initially implementing react-native-maps into a project I noticed that the iOS Simulator didn’t quite like it. Whenever the Mapview was visible on the screen, the Simulator was maxing out on something. Turns out the OpenGLES.framework that comes with XCode 9.0 – and not react-native-maps itself – is the culprit. That version is buggy and […]

Optimize React Performance

Good advice every React dev should be aware of: React is known to be blazingly fast with its Virtual DOM implementation. However, even with React’s built-in performance, there are instances when the UI can begin to feel sluggish. The primary culprit for poor performance is generating too many renders and reconciliations. We’ll cover 4 techniques […]

gpu.js – GPU Accelerated JavaScript

Amazing: gpu.js is a JavaScript library for GPGPU (General purpose computing on GPUs) in the browser. gpu.js will automatically compile specially written JavaScript functions into shader language and run them on the GPU using the WebGL API. In case WebGL is not available, the functions will still run in regular JavaScript. Only a subset of […]

Detect unnecessary renders in React with why-did-you-update

why-did-you-update is a library that hooks into React and detects potentially unnecessary component renders. It detects when a component’s render method is called despite its props their values are the same. Installation per npm, of course: npm install –save-dev why-did-you-update No need to adjust all your components either, why-did-you-update works by patching React itself: import […]

45% Faster React Stateless (Functional) Components

When using Stateless Components throughout your React app, the lifecycle events (componentWillMount, componentDidMount, etc.) are still executed. Developer Philippe Lehoux found a way to bypass these, resulting in a 45% speed improvement: What if we could skip React internals for these components? Instead of mounting them as components, let’s just call them as what they […]