Props

Props is short for Properties

interface IProps_BETClass { 
  pItems: IListItem[] 
} 

function Welcome(props) { 
  return <h1>Hello, {props.name}</h1>; 
} 

var element = <Welcome name="Better Solutions" />; 
ReactDOM.render(element, document.getElementById('root') );  

function formatDate(date) { 
  return date.toLocaleDateString(); 
} 

function Comment(props) { 
  return ( 
    <div className="Comment"> 
      <div className="UserInfo"> 
        <img 
          className="Avatar" 
          src={props.author.avatarUrl} 
          alt={props.author.name} 
        /> 
        <div className="UserInfo-name"> 
          {props.author.name} 
        </div> 
      </div> 
      <div className="Comment-text">{props.text}</div> 
      <div className="Comment-date"> 
        {formatDate(props.date)} 
      </div> 
    </div> 
  ); 
} 

const comment = { 
  date: new Date(), 
  text: 'I hope you enjoy learning React!', 
  author: { 
    name: 'Hello Kitty', 
    avatarUrl: 'https://placekitten.com/g/64/64',  
  }, 
}; 

ReactDOM.render( 
  <Comment 
    date={comment.date} 
    text={comment.text} 
    author={comment.author} 
  />, 
  document.getElementById('root')  
); 

Props are Read Only

Whether you declare a component as a function or a class, it must never modify its own props.