PropTypes.array

PropTypes.bool

PropTypes.func

PropTypes.number

PropTypes.object

PropTypes.string

propTypes is only checked in development mode

npm install --save prop-types
		

import React from 'react';
import ReactDOM from 'react-dom';
import PropTypes from 'prop-types';

class Greeting extends React.Component {
  render() {
    return (
      <h1>Hello, {this.props.name}, {this.props.age}, {this.props.address}</h1>
    );
  }
}

// default props values
Greeting.defaultProps = {
  address: '40'
};

// type checking
Greeting.propTypes = {
  name: PropTypes.string,
  age: PropTypes.string.isRequired
};

let names = ['Lin', 'Chen'];
ReactDOM.render(<Greeting name = {names}
               address="Valdosta, GA"/>, document.getElementById('root'));
		

Warning: Failed prop type: Invalid prop `name` of type `array` supplied to `Greeting`, expected `string`.
Warning: Failed prop type: The prop `age` is marked as required in `Greeting`, but its value is `undefined`.