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Frontend Armory
Level up your JavaScript through interactive exercises and examples.
Latest posts
What the this? 5 simple rules to tame JavaScript's most confusing keyword
Learn to wield JavaScript's 'this' keyword like a pro – all it takes is 5 simple rules.
Control Components: reuse react components with pseudo-selectors
Learn to use control components -- a pattern that facilitates composition of pseudo-selectors.
Is a Redux Store Observable?
Redux stores and RxJS Observables both have a subscribe method with a similar signature – but are they really the same thing?
The big 2019 Frontend Armory update
It's been a big year for Frontend Armory – with new lessons, code, videos, a new mission and a new price.
A deep dive into React effects
Learn all about React's new useEffect hook, with live exercises and fractals.
When to Use Custom React Hooks
Learn how custom hooks are like mixins: a great way to share small bits of functionality between components.
useRef() and Concurrent Mode: how to avoid shooting yourself in the foot
React's eaglerly awaited Concurrent Mode can vastly improve user experience, but it requires a stricter way of writing components.
Creating a react-redux alternative with Hooks and Proxies
Create a simple React/Redux integration with Hooks, then improve its performance with Proxies.
From React Hooks to... Render Props?
Even old-school class components allow you to compose component state. Hooks just make your life far, far simpler.
A React Router with Hooks and Suspense
Navi is a new kind of router for React, that lets you declaratively map URLs to (possibly asynchronous) content.
useContext(): a React hook that's an obvious win
Don't let the hype around hooks fool you - useContext() is actually incredibly useful.
Will it finally: a try/catch quiz
You know try and catch, but how well do you know finally? Find out with 4 live examples.
CSS-in-JS and Static Rendering
CSS-in-JS can be a huge win for maintainability. But plain CSS still has its place.
Reusable Time Travel with React Hooks and Immer
Learn how and why to make a useTimeTravel React hook that we can use to make Tolerant User Interfaces.
4 ways to pass children to React elements
Do you know all 4 ways to pass children to React elements?
React Fragments in Practice – 4 real-world examples
Learn to group React elements without unnecessary markup – using React Fragments.
Using MDX with create-react-app 2
Learn how to get the succinct syntax of Markdown, the power of JSX, and all with the simplicity of create-react-app 2.
Static vs. Server Rendering
Static rendering and server rendering both involve rendering HTML for each of your app's pages – but there's one major difference between them...
Navi: SEO & routing with vanilla create-react-app
Build big, fast, CDN-delivered websites with great SEO & SMO, and all with vanilla create-react-app!