loop inside object if key has further array code example

Example 1: javascript loop through array of objects

var people=[
  {first_name:"john",last_name:"doe"},
  {first_name:"mary",last_name:"beth"}
];
for (let i = 0; i < people.length; i++) { 
  console.log(people[i].first_name);
}

Example 2: loop array of objects

const myArray = [{x:100}, {x:200}, {x:300}];

const newArray= myArray.map(element => {
    return {
        ...element,
        x: element.x * 2
    };
});

console.log(myArray); // [100, 200, 300]
console.log(newArray); // [200, 400, 600]