Can't find TransformStream in some iOS devices

[FishHawk]

Some iOS users of my website reported that zip.js is causing an error: ReferenceError: Can't find variable: TransformStream. Even after updating or changing browsers, the problem remains. However, using the web-streams-polyfill resolves the issue.

Could this just be a browser compatibility problem? If so, why doesn't updating the browser fix it?

[gildas-lormeau]

I confirm that zip.js heavily depends on Web Streams (i.e. WritableStream, ReadableStream and TransformStream). It's pretty weird that updating browsers doesn't solve the problem. TransformStream is supposed to be supported on Safari since the version 14.1 released on 26 Apr. 2021, see https://caniuse.com/mdn-api_transformstream_transformstream.

[FishHawk]

Thanks for your answer.

After checking again, the users have not updated their iOS. Even if the browser version is updated, it remains very old. However, according to "caniuse", these browsers are still supported.

The browser versions:

• Chrome 93.0.4577.78
• Safari 14.2

[FishHawk]

It's still strange, but I think it's just a compatibility issue.