Best way to returns keys from object in an array

Question

I have an array of objects like this:

var myArray = [{
    key: 2,
    value: 10,
},
{
    key: 5,
    value: 4,
},
{
    key: 3,
    value: 8,
},
{
    key: 12,
    value: 4,
}];

How is the most elegant way to convert this array in other just with the key numbers: [2,5,3,12]?

Answer 1

Use .map:

const myKeys = myArray.map(i => i.key);

Answer 2

Use array.map

var myArray = [{
    key: 2,
    value: 10,
},
{
    key: 5,
    value: 4,
},
{
    key: 3,
    value: 8,
},
{
    key: 12,
    value: 4,
}];

console.log(myArray.map(a => a.key));