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0

I am using the following code:

 handleOwnerMode = ownerChecked => 
 this.setState(prev => ( ownerChecked, showOwner: !prev.showOwner))
 // this.setState(prev => ( ownerChecked: !prev.ownerChecked, showOwner: !prev.showOwner ))
 

Inside the render is

<Switch onChange=this.handleOwnerMode checked=this.state.ownerChecked />

OnChange, I somehow was able to receive what was changed about ownerChecked. Why is this the case? I didn't write onChange=this.handleOwnerMode(event.value) or anything like that...

Also, for setState. I normally just use this.setState( state: newState ), but now I can somehow pass in the previous state with this.setState( prev => ). Is there defined overloading somewhere that lets me do this?

Thank you.

javascript reactjs

share|improve this question

asked Mar 26 at 12:19

FranktheTankFranktheTank

12166 bronze badges

add a comment | 

0

I am using the following code:

 handleOwnerMode = ownerChecked => 
 this.setState(prev => ( ownerChecked, showOwner: !prev.showOwner))
 // this.setState(prev => ( ownerChecked: !prev.ownerChecked, showOwner: !prev.showOwner ))
 

Inside the render is

<Switch onChange=this.handleOwnerMode checked=this.state.ownerChecked />

OnChange, I somehow was able to receive what was changed about ownerChecked. Why is this the case? I didn't write onChange=this.handleOwnerMode(event.value) or anything like that...

Also, for setState. I normally just use this.setState( state: newState ), but now I can somehow pass in the previous state with this.setState( prev => ). Is there defined overloading somewhere that lets me do this?

Thank you.

javascript reactjs

share|improve this question

asked Mar 26 at 12:19

FranktheTankFranktheTank

12166 bronze badges

add a comment | 

I am using the following code:

 handleOwnerMode = ownerChecked => 
 this.setState(prev => ( ownerChecked, showOwner: !prev.showOwner))
 // this.setState(prev => ( ownerChecked: !prev.ownerChecked, showOwner: !prev.showOwner ))
 

Inside the render is

<Switch onChange=this.handleOwnerMode checked=this.state.ownerChecked />

OnChange, I somehow was able to receive what was changed about ownerChecked. Why is this the case? I didn't write onChange=this.handleOwnerMode(event.value) or anything like that...

Also, for setState. I normally just use this.setState( state: newState ), but now I can somehow pass in the previous state with this.setState( prev => ). Is there defined overloading somewhere that lets me do this?

Thank you.

javascript reactjs

share|improve this question

asked Mar 26 at 12:19

FranktheTankFranktheTank

12166 bronze badges

 handleOwnerMode = ownerChecked => 
 this.setState(prev => ( ownerChecked, showOwner: !prev.showOwner))
 // this.setState(prev => ( ownerChecked: !prev.ownerChecked, showOwner: !prev.showOwner ))
 

<Switch onChange=this.handleOwnerMode checked=this.state.ownerChecked />

share|improve this question

asked Mar 26 at 12:19

FranktheTankFranktheTank

12166 bronze badges

share|improve this question

asked Mar 26 at 12:19

FranktheTankFranktheTank

12166 bronze badges

asked Mar 26 at 12:19

FranktheTankFranktheTank

12166 bronze badges

asked Mar 26 at 12:19

FranktheTankFranktheTank

12166 bronze badges

2 Answers
2

active

oldest

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3

OnChange, I somehow was able to receive what was changed about
ownerChecked. Why is this the case? I didn't write
onChange=this.handleOwnerMode(event.value) or anything like that...

In both cases you have passed a function (callback) to "receivers". First time to Switch Component, second time to React. Each of them can call your function/callback using any parameter they want. This is how normally callbacks are used.

Is there defined overloading somewhere that lets me do this?

Yeah probably setState checks if you passed a function to it and behaves differently: e.g. gives you previous state and calls your function. If you pass an object to it, it doesn't do that.

share|improve this answer

answered Mar 26 at 12:24

giorgi moniavagiorgi moniava

14.2k33 gold badges2424 silver badges6161 bronze badges

add a comment | 

1

React events are synthetic so that even when yo do not pass any event parameters, function takes it. Take a look at these. More information 1, More information 2.

share|improve this answer

answered Mar 26 at 12:41

Yusuf AltıparmakYusuf Altıparmak

11488 bronze badges

add a comment | 

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3

OnChange, I somehow was able to receive what was changed about
ownerChecked. Why is this the case? I didn't write
onChange=this.handleOwnerMode(event.value) or anything like that...

In both cases you have passed a function (callback) to "receivers". First time to Switch Component, second time to React. Each of them can call your function/callback using any parameter they want. This is how normally callbacks are used.

Is there defined overloading somewhere that lets me do this?

Yeah probably setState checks if you passed a function to it and behaves differently: e.g. gives you previous state and calls your function. If you pass an object to it, it doesn't do that.

share|improve this answer

answered Mar 26 at 12:24

giorgi moniavagiorgi moniava

14.2k33 gold badges2424 silver badges6161 bronze badges

add a comment | 

3

OnChange, I somehow was able to receive what was changed about
ownerChecked. Why is this the case? I didn't write
onChange=this.handleOwnerMode(event.value) or anything like that...

In both cases you have passed a function (callback) to "receivers". First time to Switch Component, second time to React. Each of them can call your function/callback using any parameter they want. This is how normally callbacks are used.

Is there defined overloading somewhere that lets me do this?

Yeah probably setState checks if you passed a function to it and behaves differently: e.g. gives you previous state and calls your function. If you pass an object to it, it doesn't do that.

share|improve this answer

answered Mar 26 at 12:24

giorgi moniavagiorgi moniava

14.2k33 gold badges2424 silver badges6161 bronze badges

add a comment | 

OnChange, I somehow was able to receive what was changed about
ownerChecked. Why is this the case? I didn't write
onChange=this.handleOwnerMode(event.value) or anything like that...

In both cases you have passed a function (callback) to "receivers". First time to Switch Component, second time to React. Each of them can call your function/callback using any parameter they want. This is how normally callbacks are used.

Is there defined overloading somewhere that lets me do this?

Yeah probably setState checks if you passed a function to it and behaves differently: e.g. gives you previous state and calls your function. If you pass an object to it, it doesn't do that.

share|improve this answer

answered Mar 26 at 12:24

giorgi moniavagiorgi moniava

14.2k33 gold badges2424 silver badges6161 bronze badges

share|improve this answer

answered Mar 26 at 12:24

giorgi moniavagiorgi moniava

14.2k33 gold badges2424 silver badges6161 bronze badges

answered Mar 26 at 12:24

giorgi moniavagiorgi moniava

14.2k33 gold badges2424 silver badges6161 bronze badges

answered Mar 26 at 12:24

giorgi moniavagiorgi moniava

14.2k33 gold badges2424 silver badges6161 bronze badges

1

React events are synthetic so that even when yo do not pass any event parameters, function takes it. Take a look at these. More information 1, More information 2.

share|improve this answer

answered Mar 26 at 12:41

Yusuf AltıparmakYusuf Altıparmak

11488 bronze badges

add a comment | 

1

React events are synthetic so that even when yo do not pass any event parameters, function takes it. Take a look at these. More information 1, More information 2.

share|improve this answer

answered Mar 26 at 12:41

Yusuf AltıparmakYusuf Altıparmak

11488 bronze badges

add a comment | 

React events are synthetic so that even when yo do not pass any event parameters, function takes it. Take a look at these. More information 1, More information 2.

share|improve this answer

answered Mar 26 at 12:41

Yusuf AltıparmakYusuf Altıparmak

11488 bronze badges

share|improve this answer

answered Mar 26 at 12:41

Yusuf AltıparmakYusuf Altıparmak

11488 bronze badges

answered Mar 26 at 12:41

Yusuf AltıparmakYusuf Altıparmak

11488 bronze badges

answered Mar 26 at 12:41

Yusuf AltıparmakYusuf Altıparmak

11488 bronze badges