shouldcomponentupdate react code example

Example 1: react native class component constructor

import React from 'react';  
import { View, TextInput } from "react-native";

class App extends React.Component {  
  constructor(props){  
    super(props);  
    this.state = {  
         name: "" 
      }  
    this.handleChange = this.handleChange.bind(this);  
  }
  handleChange(text){
    this.setState({ name: text })
    console.log(this.props);  
  }  
  render() {  
    return (  
    <View>
      <TextInput 
      	value={this.state.name} 
  		onChangeText={(text) =>this.handleChange(text)}
      />
    </View>  
  }  
}  
export default App;

Example 2: componentDidUpdate

componentDidUpdate(prevProps, prevState) {
  if (prevState.pokemons !== this.state.pokemons) {
    console.log('pokemons state has changed.')
  }
}

Example 3: lifecycle method react

INITIALIZATION= setup props and state 
MOUNTING= constructor->componentWillMount->render->componentDidMount//Birth
UPDATE= shouldComponentUpdate->componentWillUpdate->render
  		->componentDidUpdate //Growth
UNMOUNTING= componentWillUnmount //Death

Example 4: shouldcomponentupdate

shouldComponentUpdate(nextProps, nextState) {
  return true;
}

Example 5: component did mmount

componentDidMount()

Example 6: shouldcomponentupdate default return

By default, shouldComponentUpdate returns true, but you can override it to return false for cases that you do not want a re-render.