Taking a function as an argument:
function applyFunctionToArray(arr, fn) { const result = []; for (let i = 0; i < arr.length; i++) { result.push(fn(arr[i])); } return result; } const numbers = [1, 2, 3, 4, 5]; function double(x) { return x * 2; } const doubledNumbers = applyFunctionToArray(numbers, double); console.log(doubledNumbers); // Output: [2, 4, 6, 8, 10]