Fix incorrect assetBase documentation

[dowski]

Description of what this PR is changing or adding, and why: Fixing a documentation bug.

Issues fixed by this PR (if any): #11341

PRs or commits this PR depends on (if any): N/A

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[sfshaza2]

lgtm

[sfshaza2]

/gcbrun

[dowski]

So actually, I just double-checked my code and the doc change I made is not right. assetBase is actually an argument to engine intializer initializeEngine, not _flutter.loader.load().

[dowski]

The assetBase arg to initializeEngine is still documented, although the whole page that contains those docs say they are for legacy versions of Flutter.

https://docs.flutter.dev/platform-integration/web/initialization-legacy#initializing-the-engine

[dowski]

Okay, I tweaked this PR to make it correct. It does feel like some restructuring of the docs is in order (assetBase is nicely documented on the "legacy" initialization page). Maybe that's part of the goal of #11320?

[sfshaza2]

/gcbrun

[flutter-website-bot]

Visit the preview URL for this PR (updated for commit 3c2842e):

https://flutter-docs-prod--pr11342-patch-1-i3il2yy4.web.app

[dowski]

Sigh

I think this is doc change is still wrong, after reading more of the code.

As long as you don't supply a custom onEntryPointLoaded callback, you can supply assetBase in the config. It will get passed to initializeEngine here.

If you do supply a custom onEntryPointLoaded callback, you must manually pass it the config that was passed to _flutter.loader.load() (or instead of passing it there? -- I'm not clear on that).

---

Maybe the real fix here is to document that the initializeEngine call should receive the same config that _flutter.loader.load() receives? What do you all think?

[dowski]

I'm going to close this and come back w/ a fresh PR focused on what I discovered above.

[johnpryan]

Thanks for sharing your findings @dowski! I haven't validated this, but am I understanding correctly that when you configureassetBase influtter.loader.load(), you need to also provide it to the onEntrypointLoaded callback? cc: @ditman @eyebrowsoffire

[dowski]

Hey @johnpryan - you're welcome.

It's more like if you pass an onEntryPointLoaded callback, assetBase gets ignored unless you manually pass it to the initializer. initializeEngine call in the callback.

I wound up filing a new focused bug that includes sample code:

flutter/flutter#158041

I didn't file it here in the website repo as I'm not sure it's strictly a documentation issue. The API feels plain hard to use.