This is my parent Component having state ( value and item ). I am trying to pass value state as a props to child component. The code executed in render method is Performing toggle when i click on button. But when i call the list function inside componentDidMount, Toggle is not working but click event is performed.
import React, { Component } from 'react'
import Card from './Components/Card/Card'
export class App extends Component {
state = {
values : new Array(4).fill(false),
item : [],
}
toggleHandler = (index) => {
console.log("CLICKED");
let stateObject = this.state.values;
stateObject.splice(index,1,!this.state.values[index]);
this.setState({ values: stateObject });
}
list = () => {
const listItem = this.state.values.map((data, index) => {
return <Card key = {index}
show = {this.state.values[index]}
toggleHandler = {() => this.toggleHandler(index)} />
})
this.setState({ item : listItem });
}
componentDidMount(){
// if this is not executed as the JSX is render method is executed everything is working fine. as props are getting update in child component.
this.list();
}
render() {
return (
<div>
{/* {this.state.values.map((data, index) => {
return <Card key = {index}
show = {this.state.values[index]}
toggleHandler = {() => this.toggleHandler(index)} />
})
} */}
{this.state.item}
</div>
)
}
}
export default App
This is my child Component where the state is passed as props
import React from 'react'
const Card = (props) => {
return (
<div>
<section>
<h1>Name : John Doe</h1>
<h3>Age : 20 </h3>
</section>
{props.show ?
<section>Skills : good at nothing</section> : null
}
<button onClick={props.toggleHandler} >Toggle</button>
</div>
)
}
export default Card
I know the componentDidMount is executed only once. but how to make it work except writing the JSX directly inside render method
Value should be mapped inside render()
of the class component in order to work
like this:
render() {
const { values } = this.state;
return (
<div>
{values.map((data, index) => {
return (
<Card
key={index}
show={values[index]}
toggleHandler={() => this.toggleHandler(index)}
/>
);
})}
</div>
);
}
check sandbox for demo
https://codesandbox.io/s/stupefied-spence-67p4f?file=/src/App.js