javascript - React: setState can only update a mounted or mounting component - Stack Overflow

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I need a setState inside a timeout in my ponent, so I've done this:

ponentDidMount() {
  this.timeouts.push(setTimeout(() => {
    this.setState({ text: 2 });
  }, 4000));
}

ponentWillUnmount() {
  this.timeouts = [];
}

But I'm getting this error:

Warning: setState(...): Can only update a mounted or mounting ponent.
This usually means you called setState() on an unmounted ponent.
This is a no-op.

What am I doing wrong?

I need a setState inside a timeout in my ponent, so I've done this:

ponentDidMount() {
  this.timeouts.push(setTimeout(() => {
    this.setState({ text: 2 });
  }, 4000));
}

ponentWillUnmount() {
  this.timeouts = [];
}

But I'm getting this error:

Warning: setState(...): Can only update a mounted or mounting ponent.
This usually means you called setState() on an unmounted ponent.
This is a no-op.

What am I doing wrong?

• javascript
• reactjs
• ponents

Share Improve this question Follow edited Mar 2, 2017 at 14:25 Matheus Lima asked Mar 2, 2017 at 14:07 Matheus LimaMatheus Lima 2,14333 gold badges3333 silver badges4949 bronze badges 13

• Before you call setState your ponent will be mounted but your ponent is not mounted – Ihor Skliar Commented Mar 2, 2017 at 14:11
• 1 @MatheusLima when your setState was called, your ponent is unmounted, don't forget you are using timeout! – Ihor Skliar Commented Mar 2, 2017 at 14:15
• 1 Does your ponent unmount within that 4 second frame? – Nick Zuber Commented Mar 2, 2017 at 14:19
• 1 @NickZuber I think that this is it! I'm probably not unmounting it properly. I'll update the question. – Matheus Lima Commented Mar 2, 2017 at 14:23
• 1 You should be clearing the timeouts when you unmount the ponent, and I think @IhorSkliar is right – Shubham Khatri Commented Mar 2, 2017 at 14:24

 |  Show 8 more ments

1 Answer 1

Sorted by: Reset to default 7

Change your ponentWillUnmount to clear the timeouts properly. You need to make use of clearTimeout to clear the timeout instead of emptying the array.

ponentDidMount() {
  this.timeouts.push(setTimeout(() => {
    this.setState({ text: 2 });
  }, 4000));
}

clearTimeouts: function() {
  this.timeouts.forEach(clearTimeout);
}

ponentWillUnmount() {
  this.clearTimeouts();
}

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