title: xProd tags: array,math,intermediate

Creates a new array out of the two supplied by creating each possible pair from the arrays.

Use Array.prototype.reduce(), Array.prototype.map() and Array.prototype.concat() to produce every possible pair from the elements of the two arrays and save them in an array.

const xProd = (a, b) =>
  a.reduce((acc, x) => acc.concat(b.map((y) => [x, y])), []);

xProd([1, 2], ["a", "b"]); // [[1, 'a'], [1, 'b'], [2, 'a'], [2, 'b']]