Functions

• Map
• Filter
• Reduce

Map

• The map() method creates a new array by calling a provided function on every element in the calling array.
• used to traverse and display a list of similar objects of a component

const [monsters, setMonsters] = useState[{id:1,name:'Linda'},{id:2,name:'Jacky'},{id:3,name:'Tom'}];
return(
    {this.state.monsters.map((eachone)=>{
       return <h1>{eachone.name}</h1>
    })}
);

Filter

• The filter() method create a new array by looping through an array and including or excluding elements based on provided condition

const names = ['James', 'John', 'Paul', 'Ringo', 'George'];
<div>
{names.filter(name => name.includes('J')).map(filteredName => (
    <li>
    {filteredName}
    </li>
))}
</div>

Reduce

• The reduce() method return the sum of all the elements in an array

const arr = [1,2,3,4,5];
const sum = arr.reduce((total,item)=>total+item,0);