JavaScript, Object Oriented, Technology, Oop.
{ const doubled = []; for (let i = 0, length = data.length; i < length; i++) { doubled[i] = data[i] * 2; } return doubled; }; // Same as above, but works for anything with the // map operation. const doubleAllInterface = data => data.map(x => x * 2); const box = value => ({ map: f => box(f(value)),