(by @andrestaltz)
If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.
Memoization is a somewhat fraught topic in the React world, meaning that it's easy to go wrong with it, for example, by [making memo() do nothing][memo-pitfall] by passing in children to a component. The general advice is to avoid memoization until the profiler tells you to optimize, but not all use cases are general, and even in the general use case you can find tricky nuances.
Discussing this topic requires some groundwork about the technical terms, and I'm placing these in once place so that it's easy to skim and skip over:
invoices/123? in a URL like /assignments?showGrades=1.# portion of the URL. This is not available to servers in request.url so its client only. By default it means which part of the page the user should be scrolled to, but developers use it for various things.
Webpack 4 automatically polyfilled many Node APIs in the browser. This was not a great system, because it could lead to surprisingly giant libraries getting pulled into your app by accident, and it gave you no control over the exact versions of the polyfills you were using.
So Webpack 5 removed this functionality. That means you need to make changes if you were relying on those polyfills. This is a quick reference for how to replace the most common patterns.
For each automatically-polyfilled node package name on the left, this shows the name of the NPM package that was used to polyfill it on the right. Under webpack 5 you can manually install these packages and use them via resolve.fallback.
This article has been given a more permanent home on my blog. Also, since it was first written, the development of the Promises/A+ specification has made the original emphasis on Promises/A seem somewhat outdated.
Promises are a software abstraction that makes working with asynchronous operations much more pleasant. In the most basic definition, your code will move from continuation-passing style:
getTweetsFor("domenic", function (err, results) {
// the rest of your code goes here.
While this gist has been shared and followed for years, I regret not giving more background. It was originally a gist for the engineering org I was in, not a "general suggestion" for any React app.
Typically I avoid folders altogether. Heck, I even avoid new files. If I can build an app with one 2000 line file I will. New files and folders are a pain.
Note:
When this guide is more complete, the plan is to move it into Prepack documentation.
For now I put it out as a gist to gather initial feedback.
If you're building JavaScript apps, you might already be familiar with some tools that compile JavaScript code to equivalent JavaScript code:
