Demo code to show that fat arrow function and binding causes re-rendering in react native

re-rendering_demo.js

import React, {PureComponent} from 'react';
import {
  View,
  Text,
  TouchableHighlight,
  TouchableOpacity,
} from 'react-native';

class Demo extends PureComponent {
  constructor(props) {
    super(props);
    this.state = {
      foo: false,
    };
  }
  
  /**
  * Press "change state" to cause re-rendering of ParentComponent. This is expected.
  * Observe the console output to see whether ChildComponent gets re-rendered as well.
  * Ideally, ChildComponent should not be re-rendered, because nothing should change
  * in ChildComponent while ParentComponent gets re-rendered.
  */
  render() {
    return (
      <View>
        <ParentComponent prop1={this.state.foo} />
        <TouchableHighlight
          onPress={() => this.setState({foo: !this.state.foo})}>
          <Text>change state</Text>
        </TouchableHighlight>
      </View>
    );
  }
}

class ChildComponent extends PureComponent {
  /**
  * Pressing "Click Me" does not cause any re-rendering. It is used to
  * show consistency of ChildComponent behavior with different return
  * statement in ParentComponent.
  */
  render() {
    console.log('ChildComponent rendered');
    return (
      <TouchableOpacity onPress={this.props.cb}>
        <View>
          <Text>Click Me</Text>
        </View>
      </TouchableOpacity>
    );
  }
}

class ParentComponent extends PureComponent {
  _print = () => console.log('clicked');

  _anotherPrint() {
    console.log(this.props.prop1);
  }

  /**
  * Test with each return statement to see whether ChildComponent re-renders
  * with ParentComponent. Note that ParentComponent is supposed to be re-rendered,
  * but ChildComponent should not be re-rendered. However, fat arrow function and
  * binding both lead to ChilComponent being re-rendered.
  */
  render() {
    console.log(`ParentComponent rendered after ${this.props.prop1}`);
    return (
      // <ChildComponent cb={() => console.log('clicked')}/>
      // <ChildComponent cb={this._print} />
      <ChildComponent cb={this._anotherPrint.bind(this)} />
    );
  }
}

export default Demo;