where to use "new Map" in javascript code example

Example 1: new map js

let utilisateurs = new Map()

utilisateurs.set('Mark Zuckerberg' ,{
    email: '[email protected]',
    poste: 'PDG',
})

utilisateurs.set ('bill Gates',{
    email: '[email protected]' ,
    poste : 'sauver le monde' ,

})
    
console.log(utilisateurs);

Example 2: how to create an element in js using the map method

const numbers = [1, 2, 3, 4, 5]; 

const bigNumbers = numbers.map(number => {
  return number * 10;
});