Notes

RequireJS in 2021

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JavaScript
2 minutes

Do we need RequireJS in 2021? Absolutely not. RequireJS was relevant 8 years ago (before ES2015 released), it’s not any more. The problem it was trying to solve (JS modules and dependency management) has been fixed natively in JavaScript.

Learning it today mainly serves two purposes. It allows you to work on legacy projects, and you get familiar with JS history. The API is not that extensive though, you can go through the docs in a day and most of the functionality and config makes sense. Any confusion you may feel as a modern JS developer who started with ES6 to begin with would arise from actually understanding why we needed RequireJS in the first place, not with how it works.

RequireJS is not the only one of it’s kind. There is also CommonJS which was the original module solution used by NodeJS. NodeJS v13 introduced experimental support for ES6 modules. You can get an idea of different module loaders and their syntax in the TypeScript docs

Well-known module loaders used in JavaScript are Node.js’s loader for CommonJS modules and the RequireJS loader for AMD modules in Web applications.

With ES2015 (ES6), we get built-in support for modules in JavaScript. Like with CommonJS, each file is its own module.

A module is just a file that exports some code that you can then import in another file

Compatibility issues

  • You can not use CommonJS syntax with ES modules syntax, they’re not interoperable
  • If you’re using TypeScript with RequireJS, keep in mind the incompatibility of default exports with AMD/CommonJS which have a single exports object as the default export

When exporting a module using export =, TypeScript-specific import module = require("module") must be used to import the module.

1import module = require('module')
2
3export = foo

What does RequireJS do?

  • code splitting into files (aka scripts or modules)
  • dependency management (which script needs what other scripts to work, load them in order)
  • path mapping (you can have clean absolute imports)
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