Fixing DRACOLoader Path Issues in Puppeteer Tests

The error you're encountering is related to Puppeteer not being able to fetch the Draco decoder files during your unit tests. This is a common issue when running tests in a headless browser environment like Puppeteer.

The Problem

The Failed to fetch error indicates that Puppeteer cannot access the Draco decoder files at the specified path. This is likely because:

1. The relative path you're using doesn't resolve correctly in the Puppeteer context
2. Puppeteer might have different permissions or access restrictions compared to your regular browser

Solutions

1. Use an Absolute Path

Instead of a relative path, try using an absolute path to the Draco decoder files:

JAVASCRIPTCopied
this.dracoLoader.setDecoderPath('/absolute/path/to/3rdParty/three.js-master/jsm/libs/draco/');

Make sure this path is accessible from the context where Puppeteer is running.

2. Serve the Files Locally During Tests

Set up a local server during your tests to serve the Draco files:

JAVASCRIPTCopied
// In your test setup
const server = http.createServer((req, res) => {
  // Serve Draco files from your local directory
});
server.listen(3000);

// Then in your test
this.dracoLoader.setDecoderPath('http://localhost:3000/draco/');

3. Mock the DRACOLoader

For unit tests, you might consider mocking the DRACOLoader to avoid the need for actual file loading:

JAVASCRIPTCopied
// Mock the DRACOLoader methods
jest.mock('three/addons/loaders/DRACOLoader.js', () => {
  return {
    DRACOLoader: jest.fn().mockImplementation(() => {
      return {
        setDecoderPath: jest.fn(),
        preload: jest.fn(),
        load: jest.fn((url, onLoad) => {
          // Create a mock geometry and call onLoad
          const mockGeometry = new THREE.BufferGeometry();
          onLoad(mockGeometry);
        })
      };
    })
  };
});

4. Use the DRACOLoader's preload Method

Make sure to call the preload method before loading any models:

JAVASCRIPTCopied
this.dracoLoader.setDecoderPath('3rdParty/three.js-master/jsm/libs/draco/');
this.dracoLoader.preload(); // Pre-fetch the decoder libraries

5. Check File Accessibility

Ensure that Puppeteer has access to the directory where the Draco files are stored. You might need to adjust file permissions or configure Puppeteer to allow access to specific directories.

Additional Considerations

• Make sure the Draco decoder files are actually present in the specified directory
• Consider using a more recent version of Three.js if you're encountering compatibility issues
• Check if your Puppeteer configuration has any network restrictions that might be blocking the file access

By implementing one or more of these solutions, you should be able to resolve the issue with loading the Draco decoder in your Puppeteer tests.