How to right map function

Syntax

let newArray = arr.map(callback(currentValue[, index[, array]]) {
  // return element for newArray, after executing something
}[, thisArg]);

Example

const arr = [1,2,5,6,10,20];

// pass a function to map
const map1 = arr.map(x => x + 2);

// x is value of each element of arr

console.log(map1);
// expected output: Array [3, 4, 7, 8,12,22]

Thankyou for reaD