Explicitly note that ref callbacks are called before componentDidMount. #216
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content/docs/refs-and-the-dom.md
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| React will call the `ref` callback with the DOM element when the component mounts, and call it with `null` when it unmounts. | |||
| React will call the `ref` callback with the DOM element when the component mounts, and call it with `null` when it unmounts. `ref` callbacks will be called before `componentDidMount`. | |||
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This new wording could be slightly confusing because ref callbacks might be called after mount if a new ref callback is provided (as is the case with arrow-functions that are recreated each time render is run). In that case, React clears the old one and calls the new one during the render phase (before componentDidMount / componentDidUpdate).
Edit: The caveat I mentioned above is mentioned later on the same docs page.
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Guh, GitHub keeps auto-submitting my comment on Enter when I don't intend it. Sorry.
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What do you think of wording more like:
refcallbacks are invoked beforecomponentDidMountorcomponentDidUpdatelifecycle hooks.
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Sounds good to me, I'll push an update.
Sync with reactjs.org @ b8b3db7
The question came up this morning on our team as to if
refcallbacks are guaranteed to be called beforecomponentDidMount. The current wording in the docs implies that the answer is "yes;" however, we did find an instance on Stack Overflow where somebody was claiming that their ref callback was called aftercomponentDidMount. That issue appears to possibly be related to using an instance-bound arrow function forrender. The following comment is also linked from that thread: facebook/react#6249 (comment)This PR simply makes the docs explicitly state that
refcallbacks will be called beforecomponentDidMount.