Calling a function in React

Question

I\'m a beginner in React, and I\'m a little confused about calling a function in React.

I saw the following ways and I don\'t know when to use each and which one.

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Answer 1

this is correct -> handleAddTodo ={this.handleAddTodo} When function passing to child component you have to bind your function like this handleAddTodo ={this.handleAddTodo.bind(this)}. below code help out your doubt.

Simple Example

import React from 'react';

class App extends React.Component {

   constructor(props) {
      super(props);

      this.state = {
         data: 'Initial data...'
      }

      this.updateState = this.updateState.bind(this);

   };

   updateState() {
      this.setState({data: 'Data updated...'})
   }

   render() {
      return (
         

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{this.state.data}
         
      );
   }
}

export default App;

Child Events

import React from 'react';

class App extends React.Component {

   constructor(props) {
      super(props);

      this.state = {
         data: 'Initial data...'
      }

      this.updateState = this.updateState.bind(this);
   };

   updateState() {
      this.setState({data: 'Data updated from the child component...'})
   }

   render() {
      return (
         

            
         
      );
   }
}

class Content extends React.Component {

   render() {
      return (
         

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{this.props.myDataProp}
         
      );
   }
}

export default App;

Refer here