Use PropTypes to Define the Props

Tell us what’s happening:
“isRequired” means?? “number type is required” or “quantity prop is required” ??

Below is the error that showed up, when isRequired is not mentioned in the code

// running test
The Items component should include a propTypes check that requires quantity to be a number.
// tests completed

Your code so far

const Items = (props) => {
  return <h1>Current Quantity of: {props.quantity}</h1>

// change code below this line
Items.propTypes ={quantity : PropTypes.number.isRequired}
// change code above this line

Items.defaultProps = {
  quantity: 0

class ShoppingCart extends React.Component {
  constructor(props) {
  render() {
    return <Items quantity={10}/>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.79 Safari/537.36.

Link to the challenge:

The second - it throws an error when the error has not been passed.

// You can chain any of the above with isRequired to make sure a warning
// is shown if the prop isn’t provided.