tp02l

index.js

// example
// don't overthink this too much
class X extends PureComponent {
  // constructor equivalent for creating initial state
  state = {
    something: ''
  }

  // function that returns another function
  changeReturn = () => e => {
    this.setState({
      [e.target.name]: e.target.value
    })
  }
  
  // function that sets controlled input value
  change = e => {
    this.setState({
      [e.target.name]: e.target.value
    })
  }

  // render
  render() {
    return (
      <div>
        Immediately called
        <input type="text" name="something" placeholder="Write something..." onChange={this.changeReturn()}>
        Not immediately called
        <input type="text" name="something" placeholder="Write something..." onChange={this.change}>
      </div>
    )
  }
}