Flatten multidimensional array exercise

exercise

/ February 19th, 2022 • quick read

Given a multidimensional array with depth of n, flatten it. Once flattened make it available as a method on array instance.

Solution:

const a = [1, [2, 3, [4, 5, [6, 7]]]];

function flatten(arr) {
  return arr.reduce((acc, curr) => {
    const isArray = Array.isArray(curr);
    const flat = isArray ? [...acc, ...curr] : [...acc, curr];
    return isArray ? flatten(flat) : flat;
  }, []);
}

Array.prototype.flatten = function () {
  return flatten(this);
};

console.log(a.flatten()); // [1,2,3,4,5,6,7]