Import Map Compatibility Issue in Three.js

You're encountering a common issue with import maps, which aren't universally supported across all browsers and devices yet, particularly on some Android devices.

The Problem

The error message Failed to resolve module specifier "three". Relative references must start with either "/", "./", or "../" indicates that the browser doesn't recognize the import map syntax, causing it to treat "three" as a relative path rather than a mapped module.

Solution: Using an Import Map Polyfill

As mentioned in the Three.js documentation, you can use an import map polyfill to support browsers that don't natively handle import maps. Here's how to implement it:

1. Add the import map polyfill script before your import map:

HTMLCopied
<!-- Import map polyfill -->
<script async src="https://unpkg.com/es-module-shims@1.6.3/dist/es-module-shims.js"></script>

<!-- Import map -->
<script type="importmap">
  {
    "imports": {
      "three": "https://cdn.jsdelivr.net/npm/three@0.170.0/build/three.module.js",
      "three/addons/": "https://cdn.jsdelivr.net/npm/three@0.170.0/examples/jsm/"
    }
  }
</script>

2. Make sure your module script has type="module":

HTMLCopied
<script type="module">
  import * as THREE from 'three';
  import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
  import { RoundedBoxGeometry } from 'three/addons/geometries/RoundedBoxGeometry.js';
  import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
  
  // Your code here
</script>

Alternative Approach

If you continue to have issues with the polyfill, you can also use direct paths as a fallback method:

JAVASCRIPTCopied
import * as THREE from 'https://cdn.jsdelivr.net/npm/three@0.170.0/build/three.module.js';
import { OrbitControls } from 'https://cdn.jsdelivr.net/npm/three@0.170.0/examples/jsm/controls/OrbitControls.js';
import { RoundedBoxGeometry } from 'https://cdn.jsdelivr.net/npm/three@0.170.0/examples/jsm/geometries/RoundedBoxGeometry.js';
import { GLTFLoader } from 'https://cdn.jsdelivr.net/npm/three@0.170.0/examples/jsm/loaders/GLTFLoader.js';

This approach bypasses the need for import maps entirely, though it's less elegant and harder to maintain if you need to update the Three.js version later.

The Three.js documentation specifically mentions this issue and suggests using the import map polyfill as a solution for broader compatibility while the standard is being more widely adopted.