navigation requests w/ StaleWhileRevalidate + broadcastUpdate = TypeError: Deferred_mjs.Deferred is not a constructor

[johnrobertcobbold]

Library Affected:
workbox-broadcast-cache-update

Browser & Platform:
Chrome

Issue or Feature Request Description:
When trying to use workbox-broadcast-cache-update for navigation requests using the StaleWhileRevalidate for which there is an update (using the Last-Modified header), I get the following error:

Uncaught (in promise) TypeError: Deferred_mjs.Deferred is not a constructor
    at BroadcastCacheUpdate._windowReadyOrTimeout (BroadcastCacheUpdate.mjs:154)
    at sendUpdate (BroadcastCacheUpdate.mjs:106)
    at BroadcastCacheUpdate.notifyIfUpdated (BroadcastCacheUpdate.mjs:112)
    at Plugin.cacheDidUpdate (Plugin.mjs:80)
    at Object.putWrapper [as put] (cacheWrapper.mjs:99)

I am already using workbox-broadcast-cache-update with native Fetch API requests on loaded pages and it's working great. Something to do here with the page not being loaded? Is there a workaround or is there is no way to use BroadcastCacheUpdate for navigation requests?

[jeffposnick]

It looks like it's this line that triggers the error:

workbox/packages/workbox-broadcast-update/BroadcastCacheUpdate.mjs

Line 169 in 7c873eb

const deferred = new Deferred();

@philipwalton, is this potentially due to some class name mangling introduced by minification?

[philipwalton]

Hmmm, it looks like the Deferred object is never exported from workbox-core/_private.mjs: https://github.com/GoogleChrome/workbox/blob/v4.3.0/packages/workbox-core/_private.mjs#L22-L32

And this passes our unit tests because we do a custom build for those, so I guess we don't cover this code path in our integrations tests.

We should probably also separately have a test to ensure _private symbols are properly exported, as this is sort of one-off logic in our build.

[philipwalton]

@goyavo the fix for this is in v4.3.1.