JAVASCRIPT

square element in array

let arr = [1, 2, 3, 4, 5, 6, 7];
let square = (item) => item * item;

function arraySq(func, arr) {
    let newArr = [];
    arr.forEach((element) => {
        newArr.push(func(element));
    });
    return  newArr;
}

console.log(arraySq(square, arr));

square a array

function(arr) {

    ret= [];

    for (var i = 0, len = arr.length; i < len; i++) {
        ret.push(arr[i] * arr[i]);
    }

    return ret;     
}