## Squared `.filter` is not the only useful array method that do loops for you. ### `map` The `.map` method is another very powerful tool once mastered, let's see it in action: ```js const time10 = [1, 2, 3, 4, 5].map((num) => { return `#${num}` }) console.log(time10) // [`#1`, `#2`, `#3`, `#4`, `#5`] ``` Map takes a function and apply it to each elements of the array. Note that map will never change the number of element of the array For example if your function return nothing: ```js const nothingX3 = [1, 2, 3].map((num) => { // Not doing anything today... }) console.log(nothingX3) // [undefined, undefined, undefined] ``` We still get an array of 3 elements, but they are `undefined`. You should use map everytime you want to repeat the same action for all elements. ### Instructions Declare a function `toSquares` that takes an array of numbers and return an array of those squared numbers **Example:** ```js const result = toSquares([1, 2, 3, 4]) console.log(result) // [1, 4, 9, 16] ```