const chunks = (a, size) => Array.from( {length: Math.ceil(a.length / size)}, (_, i) => a.slice(i * size, i * size + size) ); const array = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j']; console.log(chunks(array, 3)); console.log(chunks(array, 2));