hhy5277 / esm

ES modules in Node today!

@std/esm

This fast, small, zero dependency, package is all you need to enable ES modules in Node 4+ today!

📖 See the release post for all the details.

Getting started

1. Run npm i --save @std/esm in your app or package directory.

2. Call require("@std/esm") before importing ES modules.

   index.js

   require("@std/esm")
   module.exports = require("./main.mjs").default

For package authors with sub modules:

// Have "foo" require only "@std/esm".
require("foo")
// Sub modules work!
const bar = require("foo/bar").default

Enable ESM in the Node CLI by loading @std/esm with the -r option:

node -r @std/esm file.mjs

Enable ESM in the Node REPL by loading @std/esm upon entering:

$ node
> require("@std/esm")
@std/esm enabled
> import path from "path"
undefined
> path.join("hello", "world")
'hello/world'

Standard Features

The @std/esm loader is as spec-compliant as possible and follows Node’s rules.

👉 This means, by default, ESM requires the use of the .mjs extension.
🔓 You can unlock unambiguous .js use with the "esm":"js" option.

Out of the box @std/esm just works, no configuration necessary, and supports:

• import / export
• Dynamic import()
• Live bindings
• Loading .mjs files as ESM
• The file URI scheme
• Node 4+ support

Unlockables

Unlock extra features with "@std/esm":options or "@std":{"esm":options} in your package.json.

Note: Options are off by default and may be specified as either an object or ESM mode string.

{ "@std/esm": {
"await":	A boolean for top-level await in the main ES module
"gz":	A boolean for gzipped module support (i.e. .js.gz, .mjs.gz) webpack gzip-loader
"esm":	A string ESM mode "mjs" files as ESM (default) "all" files as ESM "js" files with import/export/"use module" as ESM
"cjs":	A boolean for CJS features in ESM __dirname and __filename require in ESM and loading ESM with require named exports of CJS modules top-level return
} }