I'm using opentype.js to modify the font files in bootstrap-icons (to strip out unused icons). It works on Windows and Android, but not on macOS or iOS. I suspected a WebKit error, but this occurs in Chrome on macOS. I also tried a WebKit browser on Windows to confirm, and it was fine.

Possible Solution

I honestly have no clue where the issue even lies. Given the scope, this might not even be an issue with opentype.js, but there's obviously
something that's causing the outputted woff not to work, while the regular one does.

Steps to Reproduce (for bugs)

I have a function that looks like this:

function strip(path: string) {
  const buffer = await readFile(path);
  
  let data = path.endsWith('.woff2')
      ? (await decompress(buffer)).slice(0) // Need to slice, for some reason the buffer has wrong size
      : new Uint8Array(buffer);

  const font = parse(data.buffer);
  
  let output = new Uint8Array(font.toArrayBuffer());
  if (path.endsWith('.woff2') {
    data = await compress(data);
  }
  
  await writeFile(path, data);
}

It deals with woff or woff2 types, which is what bootstrap-icons exports. Even without modifying the underlying font data (as in the example), this issue occurs.

Your Environment

• Version used: 1.3.1
• Font used: Bootstrap Icons
• Browser Name and version: Chrome, Safari, Otter
• Operating System and version (desktop or mobile): macOS 10.15, iOS 15, Windows 11, Android 13, Ubuntu 23.04
• Link to your project: https://github.com/Mexican-Man/vite-plugin-purge-bootstrap-icons

Here's a zip with both the working unmodified version, and the "modified and broken" one.

I apologize for the lack of useful info; I genuinely don't know how I would go about debugging such a thing. Let me know if there's anything else I can do.