isMounted() unreliable when rendering on client

[stevoland]

Looking at the test case in specs/fixtures: when browsing to the first page, getMounted() on the index page component returns true. If we click 'about', it still returns true. If we navigate back with the browser back button it now returns false.

[andreypopp]

That might be related to facebook/react#423

[andreypopp]

Hm... can't reproduce it, how do you acquire current page component? You should be able to do so via:

var app = require('react-app/runtime/browser').app;
app.page.isMounted()

Which returns true for me even if I use browser's back button.

[stevoland]

You can reproduce by, for example, adding console.info(this.isMounted()); to the pageDidMount of index.jsx.

I'll test if your React PR fixes it, thanks.

[stevoland]

No, I don't think the PR fixes it.

[stevoland]

Have spent all day looking into this and have got nowhere. Any ideas?

[andreypopp]

The problem is we bind a page's spec to a newly created Page component too early. On rendering this component into a DOM, React sees that new component and component already in DOM are of the same type and decides just to translate props into a current component instead of mounting the new component. Thus we have a spec transfered to a mounted "old" component but all methods are already bound to new component which was just discared...

[andreypopp]

I believe it is fixed now, also Page can now use state.

[andreypopp]

Published as 0.6.2.

[stevoland]

Thanks, this fixes this case but can you explain what I'm doing wrong in this example: https://github.com/stevoland/react-app/compare/callback

When returning to the index page, isMounted() is false. Is it just not possible to pass a callback from the page to a child component? Thanks!

[andreypopp]

@stevoland can you check the current master? I've merged your patch to fixtures and it now prints true in the console.

[stevoland]

Brilliant, yes this fixes this case.

However, if I then try to call this.setState() from within the callback I get an error Uncaught Error: Cyclic __proto__ value. Perhaps this is a separate issue?

[andreypopp]

@stevoland fixed

[stevoland]

Awesome. You're the man!