React: Component re-renders itself without checking into shouldComponentUpdate.

[iamsaksham]

I have a component which re-renders itself without checking condition inside the shouldComponentUpdate. Its a large app, so cant provide any fiddle. Here is the screenshot of console where 'rerender' is getting printed before 'shouldComponentUpdate'

[gaearon]

Where is rerender being logged? Are you sure shouldComponentUpdate returned false?
Unfortunately it’s very unlikely that we would be able to help without a (reduced) test case.

[iamsaksham]

shouldComponentUpdate was not even called before rerendering the component. This screenshot might help. I'll try to code a reduced test case in a few hours.

[syranide]

I guess it would be helpful if you could print the stacktraces instead of just logging? That might save you from having to produce a reduced test case if you're lucky :)

Also, assuming everything actually works as it should. Have you tried logging mount/unmount as well? It might be that for some reason it's being unmounted and mounted, lack of shouldComponentUpdate makes total sense in that case. This would be my guess.

[aweary]

Not really related, but I can't imagine that calling ReactDOM.findDOMNode and innerHTML in shouldComponentUpdate is the best way to determine if an update is necessary.

[thymikee]

Looks like you're using Chrome (am I right?). If so, please check this V8 JIT issue and try running the code in another browser.

[keyz]

Is there any chance that you are using this.forceUpdate()?

[iamsaksham]

@syranide Excellent guess, component gets unmounted and re-mounted again. I'll close the issue for now, will re-check the issue why the component gets unmounted and will reopen if needed.

@keyanzhang There is no this.forceUpdate() in my app. Issue is caused due to unexpeced unmounting of component

@thymikee It works all the same in other browsers too. Issue is component gets unmounted unexpectedly