@std/esm

@std/esm

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

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

Defaults are important. The @std/esm loader strives to be as spec-compliant as possible while following Node’s planned built-in behaviors. This means, by default, ESM requires the use of the .mjs extension.

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

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

Note: You can unlock unambiguous .js use with the "esm":"js" option.

Unlockables

Developers have strong opinions on just about everything. To accommodate, @std/esm allows unlocking extra features with the "@std/esm" or "@std":{"esm":{}} field in your package.json.

Note: All options are off by default.

{ "@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
} }