Warning: setState(...): Can only update a mounted or mounting component.

[ramusus]

Using versions 1.8.3 and 2.0.0beta I got this error. It happens every time, when I unmount my component before onDocumentLoad is called. I don't want to use this.isMounted() because it's considered anti-pattern. So is there any way to unsubscribe from async actions in componentWillUnmount? I think it should be somewhere inside Document component

warning.js:36 Warning: setState(...): Can only update a mounted or mounting component. This usually means you called setState() on an unmounted component. This is a no-op. Please check the code for the PageTextContent component.

printWarning @ warning.js:36
warning @ warning.js:60
getInternalInstanceReadyForUpdate @ ReactUpdateQueue.js:48
enqueueSetState @ ReactUpdateQueue.js:200
ReactComponent.setState @ ReactBaseClasses.js:64
PageTextContent._this.onGetTextSuccess @ PageTextContent.js:64
Promise resolved (async)
getTextContent @ PageTextContent.js:135
componentDidMount @ PageTextContent.js:111
(anonymous) @ ReactCompositeComponent.js:265
measureLifeCyclePerf @ ReactCompositeComponent.js:75
(anonymous) @ ReactCompositeComponent.js:264
notifyAll @ CallbackQueue.js:76
close @ ReactReconcileTransaction.js:80
closeAll @ Transaction.js:206
perform @ Transaction.js:153
perform @ Transaction.js:140
perform @ ReactUpdates.js:89
flushBatchedUpdates @ ReactUpdates.js:172
closeAll @ Transaction.js:206
perform @ Transaction.js:153
batchedUpdates @ ReactDefaultBatchingStrategy.js:62
enqueueUpdate @ ReactUpdates.js:200
enqueueUpdate @ ReactUpdateQueue.js:24
enqueueSetState @ ReactUpdateQueue.js:209
ReactComponent.setState @ ReactBaseClasses.js:64
Page._this.onLoadSuccess @ Page.js:54
Promise resolved (async)
loadPage @ Page.js:151
componentDidMount @ Page.js:86
(anonymous) @ ReactCompositeComponent.js:265
measureLifeCyclePerf @ ReactCompositeComponent.js:75
(anonymous) @ ReactCompositeComponent.js:264
notifyAll @ CallbackQueue.js:76
close @ ReactReconcileTransaction.js:80
closeAll @ Transaction.js:206
perform @ Transaction.js:153
perform @ Transaction.js:140
perform @ ReactUpdates.js:89
flushBatchedUpdates @ ReactUpdates.js:172
closeAll @ Transaction.js:206
perform @ Transaction.js:153
batchedUpdates @ ReactDefaultBatchingStrategy.js:62
enqueueUpdate @ ReactUpdates.js:200
enqueueUpdate @ ReactUpdateQueue.js:24
enqueueSetState @ ReactUpdateQueue.js:209
ReactComponent.setState @ ReactBaseClasses.js:64
Document._this.onLoadSuccess @ Document.js:69
Promise resolved (async)
PDFDocumentLoadingTask_then @ pdf.js:2007
Document._this.onSourceSuccess @ Document.js:61
Promise resolved (async)
loadDocument @ Document.js:206
componentDidMount @ Document.js:149
(anonymous) @ ReactCompositeComponent.js:265
measureLifeCyclePerf @ ReactCompositeComponent.js:75
(anonymous) @ ReactCompositeComponent.js:264
notifyAll @ CallbackQueue.js:76
close @ ReactReconcileTransaction.js:80
closeAll @ Transaction.js:206
perform @ Transaction.js:153
perform @ Transaction.js:140
perform @ ReactUpdates.js:89
flushBatchedUpdates @ ReactUpdates.js:172
close @ ReactUpdates.js:47
closeAll @ Transaction.js:206
perform @ Transaction.js:153
perform @ ReactUpdates.js:89
flushBatchedUpdates @ ReactUpdates.js:172
closeAll @ Transaction.js:206
perform @ Transaction.js:153
batchedUpdates @ ReactDefaultBatchingStrategy.js:62
batchedUpdates @ ReactUpdates.js:97
dispatchEvent @ ReactEventListener.js:147

[wojtekmaj]

Hey, thanks for the report. I can confirm that this indeed is happening.

I could just set up flags which simulate isMounted on my own, but I'm not sure if we want that. I'd rather cancel a running task instead.

Sadly, it seems like the only way I can cancel a PDF.js task is to destroy it, which for some reason also happens to destroy worker altogether, which makes ReactPDF to fail to re-initialize when necessary. I don't know if I succeed at it alone, but any help is appreciated!

[wojtekmaj]

Decided to implement cancellable promises. Coming in the 2.0.0 release (and it's in freshly released beta too)!

I'm still looking for feedback whether we could do it better, but this should work just fine.