TypeScript + React: Avoid setState on unmounted components
I know that a common pattern of avoiding calling .setState() on an unmounted component is by adding a private property such as _isMounted to keep track of it, as mentioned in a blog.
I've been using this method like this:
class Hello extends React.PureComponent{
_isMounted = false;
constructor(props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
// ...
}
Everything was fine until I started to use TypeScript. I tried to do this in the same way:
class Hello extends React.PureComponent<Props, State> {
private _isMounted: boolean;
constructor(props: Props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
}
But then it always throws a type error:
TypeError: Cannot set property _isMounted of #<Component> which has only a getter
For now, the only solution I know is to explicitly write a setter for it. But I don't really understand if this is the expected way to do it. Doesn't TypeScript generate getter and setter automatically?
Updated:
A codesandbox example: https://codesandbox.io/s/l59wnqy5zz
reactjs typescript
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
|
show 1 more comment
I know that a common pattern of avoiding calling .setState() on an unmounted component is by adding a private property such as _isMounted to keep track of it, as mentioned in a blog.
I've been using this method like this:
class Hello extends React.PureComponent{
_isMounted = false;
constructor(props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
// ...
}
Everything was fine until I started to use TypeScript. I tried to do this in the same way:
class Hello extends React.PureComponent<Props, State> {
private _isMounted: boolean;
constructor(props: Props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
}
But then it always throws a type error:
TypeError: Cannot set property _isMounted of #<Component> which has only a getter
For now, the only solution I know is to explicitly write a setter for it. But I don't really understand if this is the expected way to do it. Doesn't TypeScript generate getter and setter automatically?
Updated:
A codesandbox example: https://codesandbox.io/s/l59wnqy5zz
reactjs typescript
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
I think the problem must be in code you haven't shown. In theHelloclass shown,_isMountedis clearly a data property, not an accessor property.
– T.J. Crowder
Nov 21 '18 at 14:57
The playground is happy with it (removed the React-isms, which shouldn't matter).
– T.J. Crowder
Nov 21 '18 at 14:58
I think _isMounted is a private property of React.Component. Rename it and it should work.
– Stramski
Nov 21 '18 at 15:13
1
or better yet, teardown any async stuff when unmount happens. eg if you havesetTimeout/Interval, keep a reference and callclearTimeout. reactjs.org/blog/2015/12/16/ismounted-antipattern.html
– Dimitar Christoff
Nov 21 '18 at 15:17
@Stramski Yes it did work when I change the name! Thanks! But why didn't the private property we define here overwrite the one from React.Component?
– catlicechew
Nov 21 '18 at 15:24
|
show 1 more comment
I know that a common pattern of avoiding calling .setState() on an unmounted component is by adding a private property such as _isMounted to keep track of it, as mentioned in a blog.
I've been using this method like this:
class Hello extends React.PureComponent{
_isMounted = false;
constructor(props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
// ...
}
Everything was fine until I started to use TypeScript. I tried to do this in the same way:
class Hello extends React.PureComponent<Props, State> {
private _isMounted: boolean;
constructor(props: Props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
}
But then it always throws a type error:
TypeError: Cannot set property _isMounted of #<Component> which has only a getter
For now, the only solution I know is to explicitly write a setter for it. But I don't really understand if this is the expected way to do it. Doesn't TypeScript generate getter and setter automatically?
Updated:
A codesandbox example: https://codesandbox.io/s/l59wnqy5zz
reactjs typescript
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
I know that a common pattern of avoiding calling .setState() on an unmounted component is by adding a private property such as _isMounted to keep track of it, as mentioned in a blog.
I've been using this method like this:
class Hello extends React.PureComponent{
_isMounted = false;
constructor(props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
// ...
}
Everything was fine until I started to use TypeScript. I tried to do this in the same way:
class Hello extends React.PureComponent<Props, State> {
private _isMounted: boolean;
constructor(props: Props) {
super(props);
this.state = {
// ...
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
}
But then it always throws a type error:
TypeError: Cannot set property _isMounted of #<Component> which has only a getter
For now, the only solution I know is to explicitly write a setter for it. But I don't really understand if this is the expected way to do it. Doesn't TypeScript generate getter and setter automatically?
Updated:
A codesandbox example: https://codesandbox.io/s/l59wnqy5zz
reactjs typescript
reactjs typescript
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
edited Nov 21 '18 at 15:25
catlicechew
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
asked Nov 21 '18 at 14:53
catlicechewcatlicechew
415
415
I think the problem must be in code you haven't shown. In theHelloclass shown,_isMountedis clearly a data property, not an accessor property.
– T.J. Crowder
Nov 21 '18 at 14:57
The playground is happy with it (removed the React-isms, which shouldn't matter).
– T.J. Crowder
Nov 21 '18 at 14:58
I think _isMounted is a private property of React.Component. Rename it and it should work.
– Stramski
Nov 21 '18 at 15:13
1
or better yet, teardown any async stuff when unmount happens. eg if you havesetTimeout/Interval, keep a reference and callclearTimeout. reactjs.org/blog/2015/12/16/ismounted-antipattern.html
– Dimitar Christoff
Nov 21 '18 at 15:17
@Stramski Yes it did work when I change the name! Thanks! But why didn't the private property we define here overwrite the one from React.Component?
– catlicechew
Nov 21 '18 at 15:24
|
show 1 more comment
I think the problem must be in code you haven't shown. In theHelloclass shown,_isMountedis clearly a data property, not an accessor property.
– T.J. Crowder
Nov 21 '18 at 14:57
The playground is happy with it (removed the React-isms, which shouldn't matter).
– T.J. Crowder
Nov 21 '18 at 14:58
I think _isMounted is a private property of React.Component. Rename it and it should work.
– Stramski
Nov 21 '18 at 15:13
1
or better yet, teardown any async stuff when unmount happens. eg if you havesetTimeout/Interval, keep a reference and callclearTimeout. reactjs.org/blog/2015/12/16/ismounted-antipattern.html
– Dimitar Christoff
Nov 21 '18 at 15:17
@Stramski Yes it did work when I change the name! Thanks! But why didn't the private property we define here overwrite the one from React.Component?
– catlicechew
Nov 21 '18 at 15:24
I think the problem must be in code you haven't shown. In the
Hello class shown, _isMounted is clearly a data property, not an accessor property.– T.J. Crowder
Nov 21 '18 at 14:57
I think the problem must be in code you haven't shown. In the
Hello class shown, _isMounted is clearly a data property, not an accessor property.– T.J. Crowder
Nov 21 '18 at 14:57
The playground is happy with it (removed the React-isms, which shouldn't matter).
– T.J. Crowder
Nov 21 '18 at 14:58
The playground is happy with it (removed the React-isms, which shouldn't matter).
– T.J. Crowder
Nov 21 '18 at 14:58
I think _isMounted is a private property of React.Component. Rename it and it should work.
– Stramski
Nov 21 '18 at 15:13
I think _isMounted is a private property of React.Component. Rename it and it should work.
– Stramski
Nov 21 '18 at 15:13
1
1
or better yet, teardown any async stuff when unmount happens. eg if you have
setTimeout / Interval, keep a reference and call clearTimeout. reactjs.org/blog/2015/12/16/ismounted-antipattern.html– Dimitar Christoff
Nov 21 '18 at 15:17
or better yet, teardown any async stuff when unmount happens. eg if you have
setTimeout / Interval, keep a reference and call clearTimeout. reactjs.org/blog/2015/12/16/ismounted-antipattern.html– Dimitar Christoff
Nov 21 '18 at 15:17
@Stramski Yes it did work when I change the name! Thanks! But why didn't the private property we define here overwrite the one from React.Component?
– catlicechew
Nov 21 '18 at 15:24
@Stramski Yes it did work when I change the name! Thanks! But why didn't the private property we define here overwrite the one from React.Component?
– catlicechew
Nov 21 '18 at 15:24
|
show 1 more comment
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I think the problem must be in code you haven't shown. In the
Helloclass shown,_isMountedis clearly a data property, not an accessor property.– T.J. Crowder
Nov 21 '18 at 14:57
The playground is happy with it (removed the React-isms, which shouldn't matter).
– T.J. Crowder
Nov 21 '18 at 14:58
I think _isMounted is a private property of React.Component. Rename it and it should work.
– Stramski
Nov 21 '18 at 15:13
1
or better yet, teardown any async stuff when unmount happens. eg if you have
setTimeout/Interval, keep a reference and callclearTimeout. reactjs.org/blog/2015/12/16/ismounted-antipattern.html– Dimitar Christoff
Nov 21 '18 at 15:17
@Stramski Yes it did work when I change the name! Thanks! But why didn't the private property we define here overwrite the one from React.Component?
– catlicechew
Nov 21 '18 at 15:24