JAVASCRIPT

map function in react

function NameList() {
	const names = ['Bruce', 'Clark', 'Diana']
    return (
    	<div>
      {names.map(name => <h2>{name}</h2>)}
      	</div>
    )
}

react array.map with return

const robots = ['Bruce', 'Clark', 'Diana']

robots.map((robot, index) => {
                    return (
                        <h1 key={index}>{robot} </h1>
                    )
})

map an array in react

//lets say we have an array of objects called data
<div className="sample">
  {data.map((item)=>{
    return(
  <div key={item.id} className="objectname">
    <p>{item.property1}</p>
    <p>{item.property2}</p>
  </div>
    );
  });
</div>

map method in react

function ShowName() {
  const userNames = ["Kunal", "Braj", "Sagar", "Akshay"];
  
  return (
    <>
      <div>
            { 
              
              userNames.map((elem) => {
              <h1>{elem}</h1>
              })
            
            }
          </div> 
    </>
  );
}

export default ShowName;

react map component in

render() {
	return (
      	// using a arrow function get the looping item and it's index (i)
		this.state.data.map((item, i) => {
		  <li key={i}>Test</li>
		})
	);
}

new Map() collection in react state

function MapComponent(){
  const [myMap, setMyMap] = useState(new Map());
  const updateMap = (k,v) => {
    setMyMap(new Map(myMap.set(k,v)));
  }
  return(
    <ul>
      {[...myMap.keys()].map(k => (
        <li key={k}>myMap.get(k)</li>
      ))}
    </ul>
  );
}

map in react

const array={{firstName:"x", lastName:"y"},{firstName:"a", lastName:"b"}}

// Method 1: Without using "{}"
array.map((item)=>(
  <ComponentName fName={item.firstName} lName={item.lastName} />
));

// Method 2: With using "{}"
array.map((item)=>{
  return(<ComponentName fName={item.firstName} lName={item.lastName} />)
});

how to map array in react

export const Articles = props => {
  const [articles, setArticle] = React.useState(props.data || [])
  React.useEffect(() => {
    if (Array.isArray(articles) && articles.length < 1) {
      setArticle([
        {
          title: 'how to map array in react',
          content: `read this code!`,
        },
      ])
    }
  }, [articles])
  return (
    <div>
      {Array.isArray(articles) &&
        articles.map((item, key) => (
          <article key={key}>
            <h2>{item.title}</h2>
            <p>{item.content}</p>
          </article>
        ))}
    </div>
  )
}