freeCodeCamp Challenge Guide: Pass a Callback as Props

Pass a Callback as Props


Problem Explanation

  • Add the GetInput component to the render method in MyApp, then pass it a prop called input assigned to inputValue from MyApp’s state. Also create a prop called handleChange and pass the input handler handleChange to it.
  • Add RenderInput to the render method in MyApp, then create a prop called input and pass the inputValue from state to it.

Hints

Hint 1

state is a property of Myapp class, so use ‘this.state’ to get the object value

Hint 2

To learn more about state and props, read State and Lifecycle and Components and Props.


Solutions

Solution 1 (Click to Show/Hide)
class MyApp extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      inputValue: ''
    }
  this.handleChange = this.handleChange.bind(this);
  }
  handleChange(event) {
    this.setState({
      inputValue: event.target.value
    });
  }
  render() {
    return (
       <div>
         <GetInput
           input={this.state.inputValue}
           handleChange={this.handleChange}/>
         <RenderInput
           input={this.state.inputValue}/>
       </div>
    );
  }
};

class GetInput extends React.Component {
  constructor(props) {
    super(props);
  }
  render() {
    return (
      <div>
        <h3>Get Input:</h3>
        <input
          value={this.props.input}
          onChange={this.props.handleChange}/>
      </div>
    );
  }
};

class RenderInput extends React.Component {
  constructor(props) {
    super(props);
  }
  render() {
    return (
      <div>
        <h3>Input Render:</h3>
        <p>{this.props.input}</p>
      </div>
    );
  }
};
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