freeCodeCamp Intermediate Algorithm Scripting: Steamroller

steamrollArray.js

// Flatten a nested array. You must account for varying levels of nesting.

function steamrollArray(arr) {
  // I'm a steamroller, baby

   return arr.reduce((acc, val) => Array.isArray(val) ? acc.concat(steamrollArray(val)) : acc.concat(val), []);
}

steamrollArray([1, [2], [3, [[4]]]]); // [1, 2, 3, 4]
steamrollArray([[["a"]], [["b"]]]); // ["a", "b"].
steamrollArray([1, [], [3, [[4]]]]); // [1, 3, 4].
steamrollArray([1, {}, [3, [[4]]]]); // [1, {}, 3, 4].