Methods inside of functional components
I'm experiencing a strange issue where the onPress function of a functional child component is triggered whenever the component is rendered.
Relevant parent code which renders the child component from a list of dates. I was also having issues with array.map if the component was a class component, but that's a separate issue.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
/>);
And the child component:
const ChildComponent = ({ props }) => {
let date = props.date;
const someFunction = () => {
console.log(date)
}
return (
<Text><Icon name="angle-right" onPress={someFunction()}/></Text>
)
And what I get from the console upon rendering the relevant scene:
2018-11-11
2018-11-12
2018-11-13
2018-11-14
2018-11-15
2018-11-16
Pressing the icon does nothing, yet it seems to run the function as if it was a lifecycle component. I've also moved the function into the parent component and passed it to the child as recommended per Guruparan Giritharan, and it still executes on render.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
someFunction={this.someFunction} // function now within parent component
/>);
And the updated child:
const ChildComponent = ({ props, someFunction }) => {
return (
<Text>
<Icon name="angle-right" onPress={someFunction(props.date)}/>
</Text>
)
}
react-native jsx
asked Nov 13 '18 at 5:03
NathanLNathanL
769
add a comment |
I'm experiencing a strange issue where the onPress function of a functional child component is triggered whenever the component is rendered.
Relevant parent code which renders the child component from a list of dates. I was also having issues with array.map if the component was a class component, but that's a separate issue.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
/>);
And the child component:
const ChildComponent = ({ props }) => {
let date = props.date;
const someFunction = () => {
console.log(date)
}
return (
<Text><Icon name="angle-right" onPress={someFunction()}/></Text>
)
And what I get from the console upon rendering the relevant scene:
2018-11-11
2018-11-12
2018-11-13
2018-11-14
2018-11-15
2018-11-16
Pressing the icon does nothing, yet it seems to run the function as if it was a lifecycle component. I've also moved the function into the parent component and passed it to the child as recommended per Guruparan Giritharan, and it still executes on render.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
someFunction={this.someFunction} // function now within parent component
/>);
And the updated child:
const ChildComponent = ({ props, someFunction }) => {
return (
<Text>
<Icon name="angle-right" onPress={someFunction(props.date)}/>
</Text>
)
}
react-native jsx
asked Nov 13 '18 at 5:03
NathanLNathanL
769
add a comment |
I'm experiencing a strange issue where the onPress function of a functional child component is triggered whenever the component is rendered.
Relevant parent code which renders the child component from a list of dates. I was also having issues with array.map if the component was a class component, but that's a separate issue.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
/>);
And the child component:
const ChildComponent = ({ props }) => {
let date = props.date;
const someFunction = () => {
console.log(date)
}
return (
<Text><Icon name="angle-right" onPress={someFunction()}/></Text>
)
And what I get from the console upon rendering the relevant scene:
2018-11-11
2018-11-12
2018-11-13
2018-11-14
2018-11-15
2018-11-16
Pressing the icon does nothing, yet it seems to run the function as if it was a lifecycle component. I've also moved the function into the parent component and passed it to the child as recommended per Guruparan Giritharan, and it still executes on render.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
someFunction={this.someFunction} // function now within parent component
/>);
And the updated child:
const ChildComponent = ({ props, someFunction }) => {
return (
<Text>
<Icon name="angle-right" onPress={someFunction(props.date)}/>
</Text>
)
}
react-native jsx
asked Nov 13 '18 at 5:03
NathanLNathanL
769
I'm experiencing a strange issue where the onPress function of a functional child component is triggered whenever the component is rendered.
Relevant parent code which renders the child component from a list of dates. I was also having issues with array.map if the component was a class component, but that's a separate issue.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
/>);
And the child component:
const ChildComponent = ({ props }) => {
let date = props.date;
const someFunction = () => {
console.log(date)
}
return (
<Text><Icon name="angle-right" onPress={someFunction()}/></Text>
)
And what I get from the console upon rendering the relevant scene:
2018-11-11
2018-11-12
2018-11-13
2018-11-14
2018-11-15
2018-11-16
Pressing the icon does nothing, yet it seems to run the function as if it was a lifecycle component. I've also moved the function into the parent component and passed it to the child as recommended per Guruparan Giritharan, and it still executes on render.
return list_items.map(data =>
<ChildComponent
key={data.day}
props={data}
someFunction={this.someFunction} // function now within parent component
/>);
And the updated child:
const ChildComponent = ({ props, someFunction }) => {
return (
<Text>
<Icon name="angle-right" onPress={someFunction(props.date)}/>
</Text>
)
}
react-native jsx
react-native jsx
asked Nov 13 '18 at 5:03
NathanLNathanL
769
asked Nov 13 '18 at 5:03
NathanLNathanL
769
edited Nov 13 '18 at 16:50
NathanL
asked Nov 13 '18 at 5:03
NathanLNathanL
769
asked Nov 13 '18 at 5:03
NathanLNathanL
769
asked Nov 13 '18 at 5:03
NathanLNathanL
769
769
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Change to
<Text><Icon name="angle-right" onPress={someFunction}/></Text>
You are calling the function there itself instead of passing the reference. So the function is called inside each render instead of onPress.
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
I changed it so that the function exists inside of the parent component and is being called by the child component, yet no change.
– NathanL
Nov 13 '18 at 16:44
1
Do you pass the function of parent component as a prop ?, do you get the console log when you press the icon ?
– Guruparan Giritharan
Nov 13 '18 at 16:49
1
you are calling the function on render onPress={someFunction(props.date)} thats the problem it should be a reference onPress={this.props.someFunction}
– Guruparan Giritharan
Nov 13 '18 at 17:00
1
if you need to use someFunction in your onPress along with date the way will be <Icon name="angle-right" onPress={()=>someFunction(props.date)}/>
– Guruparan Giritharan
Nov 13 '18 at 17:11
1
I changed it back to a class-based component and it worked.
– NathanL
Nov 13 '18 at 17:21
|
show 3 more comments
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Change to
<Text><Icon name="angle-right" onPress={someFunction}/></Text>
You are calling the function there itself instead of passing the reference. So the function is called inside each render instead of onPress.
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
I changed it so that the function exists inside of the parent component and is being called by the child component, yet no change.
– NathanL
Nov 13 '18 at 16:44
1
Do you pass the function of parent component as a prop ?, do you get the console log when you press the icon ?
– Guruparan Giritharan
Nov 13 '18 at 16:49
1
you are calling the function on render onPress={someFunction(props.date)} thats the problem it should be a reference onPress={this.props.someFunction}
– Guruparan Giritharan
Nov 13 '18 at 17:00
1
if you need to use someFunction in your onPress along with date the way will be <Icon name="angle-right" onPress={()=>someFunction(props.date)}/>
– Guruparan Giritharan
Nov 13 '18 at 17:11
1
I changed it back to a class-based component and it worked.
– NathanL
Nov 13 '18 at 17:21
|
show 3 more comments
Change to
<Text><Icon name="angle-right" onPress={someFunction}/></Text>
You are calling the function there itself instead of passing the reference. So the function is called inside each render instead of onPress.
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
I changed it so that the function exists inside of the parent component and is being called by the child component, yet no change.
– NathanL
Nov 13 '18 at 16:44
1
Do you pass the function of parent component as a prop ?, do you get the console log when you press the icon ?
– Guruparan Giritharan
Nov 13 '18 at 16:49
1
you are calling the function on render onPress={someFunction(props.date)} thats the problem it should be a reference onPress={this.props.someFunction}
– Guruparan Giritharan
Nov 13 '18 at 17:00
1
if you need to use someFunction in your onPress along with date the way will be <Icon name="angle-right" onPress={()=>someFunction(props.date)}/>
– Guruparan Giritharan
Nov 13 '18 at 17:11
1
I changed it back to a class-based component and it worked.
– NathanL
Nov 13 '18 at 17:21
|
show 3 more comments
Change to
<Text><Icon name="angle-right" onPress={someFunction}/></Text>
You are calling the function there itself instead of passing the reference. So the function is called inside each render instead of onPress.
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
Change to
<Text><Icon name="angle-right" onPress={someFunction}/></Text>
You are calling the function there itself instead of passing the reference. So the function is called inside each render instead of onPress.
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
answered Nov 13 '18 at 6:32
Guruparan GiritharanGuruparan Giritharan
4651618
4651618
I changed it so that the function exists inside of the parent component and is being called by the child component, yet no change.
– NathanL
Nov 13 '18 at 16:44
1
Do you pass the function of parent component as a prop ?, do you get the console log when you press the icon ?
– Guruparan Giritharan
Nov 13 '18 at 16:49
1
you are calling the function on render onPress={someFunction(props.date)} thats the problem it should be a reference onPress={this.props.someFunction}
– Guruparan Giritharan
Nov 13 '18 at 17:00
1
if you need to use someFunction in your onPress along with date the way will be <Icon name="angle-right" onPress={()=>someFunction(props.date)}/>
– Guruparan Giritharan
Nov 13 '18 at 17:11
1
I changed it back to a class-based component and it worked.
– NathanL
Nov 13 '18 at 17:21
|
show 3 more comments
I changed it so that the function exists inside of the parent component and is being called by the child component, yet no change.
– NathanL
Nov 13 '18 at 16:44
1
Do you pass the function of parent component as a prop ?, do you get the console log when you press the icon ?
– Guruparan Giritharan
Nov 13 '18 at 16:49
1
you are calling the function on render onPress={someFunction(props.date)} thats the problem it should be a reference onPress={this.props.someFunction}
– Guruparan Giritharan
Nov 13 '18 at 17:00
1
if you need to use someFunction in your onPress along with date the way will be <Icon name="angle-right" onPress={()=>someFunction(props.date)}/>
– Guruparan Giritharan
Nov 13 '18 at 17:11
1
I changed it back to a class-based component and it worked.
– NathanL
Nov 13 '18 at 17:21
I changed it so that the function exists inside of the parent component and is being called by the child component, yet no change.
– NathanL
Nov 13 '18 at 16:44
I changed it so that the function exists inside of the parent component and is being called by the child component, yet no change.
– NathanL
Nov 13 '18 at 16:44
1
1
Do you pass the function of parent component as a prop ?, do you get the console log when you press the icon ?
– Guruparan Giritharan
Nov 13 '18 at 16:49
Do you pass the function of parent component as a prop ?, do you get the console log when you press the icon ?
– Guruparan Giritharan
Nov 13 '18 at 16:49
1
1
you are calling the function on render onPress={someFunction(props.date)} thats the problem it should be a reference onPress={this.props.someFunction}
– Guruparan Giritharan
Nov 13 '18 at 17:00
you are calling the function on render onPress={someFunction(props.date)} thats the problem it should be a reference onPress={this.props.someFunction}
– Guruparan Giritharan
Nov 13 '18 at 17:00
1
1
if you need to use someFunction in your onPress along with date the way will be <Icon name="angle-right" onPress={()=>someFunction(props.date)}/>
– Guruparan Giritharan
Nov 13 '18 at 17:11
if you need to use someFunction in your onPress along with date the way will be <Icon name="angle-right" onPress={()=>someFunction(props.date)}/>
– Guruparan Giritharan
Nov 13 '18 at 17:11
1
1
I changed it back to a class-based component and it worked.
– NathanL
Nov 13 '18 at 17:21
I changed it back to a class-based component and it worked.
– NathanL
Nov 13 '18 at 17:21
|
show 3 more comments
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