Chunk Load Timeout

[espretto]

🙋 feature request

The timeout for script tags loading chunks should be configurable.

🤔 Expected Behavior

The configured timeout should apply to script tags loading chunks.

😯 Current Behavior

The timeout for script tags loading chunks is currently left up to the browser implementation. iOS v17.5 has a much shorter timeout (120sec) than most other browsers (5min)

💁 Possible Solution

A config variable needs to be created and consumed by the code section below. Ideally, the timeout would be approached w/ a retry strategy if the browser's native timeout is shorter.

parcel/packages/runtimes/js/src/helpers/browser/js-loader.js

Line 26 in 96d8814

script.onerror = function (e) {

🔦 Context

I am recording a constant percentage of non-trivial traffic failing to lazy-load chunks w/ parcel missing out on crucial functionality (consent management platform).

💻 Examples

Webpack has an option chunkLoadTimeout. This should be very useful to parcel users as well.

[devongovett]

Most of the time we don't use that loader. It's only used if the browser target doesn't support ES modules natively, which is now very rare. I don't think there's a way to configure the native dynamic import() timeout.

[espretto]

Alright, I cannot share the full sentry issue here but most events are reported by devices with iOS 17 & 18. Those usually support dynamic imports so maybe the feature detection/fallback mechanism doesn't work as expected? EDIT: Or maybe the build target is set too low?

I see that import() doesn't allow to configure a timeout directly but if the returned promise is rejected sooner than the proposed/configured timeout, this could trigger a retry-strategy.