JavaScript Import Map

An import map is JSON that browsers use to resolve the path of JS modules when used in import and import() statements.

An example can be found on three.js:

<script type="importmap">
  {
    "imports": {
      "three": "https://unpkg.com/three@0.149.0/build/three.module.js"
    }
  }
</script>

<script type="module">
  import * as THREE from 'three';
  const scene = new THREE.Scene();
</script>

Another example commonly seen in micro-frontends:

<script type="importmap">
  {
    "imports": {
      "react": "https://unpkg.com/react@18.2.0/umd/react.production.min.js",
      "react-dom": "https://unpkg.com/react-dom@18.2.0/umd/react-dom.production.min.js"
    }
  }
</script>

<script type="module">
  import * as React from 'react';
  import * as ReactDOM from 'react-dom';
</script>