flatten

flatten(array) → array · Array

Remove one level of array nesting. Each element that is an array is unwrapped; non-array elements are kept as-is.

• array (required): the nested array to flatten

{
  flat: flatten([[1, 2], [3, 4], [5]]),
  // [1, 2, 3, 4, 5]
  mixed: flatten([[1, 2], 3, [4, 5]]),
  // [1, 2, 3, 4, 5]
  oneLevel: flatten([[[1, 2]], [[3]]])
  // [[1, 2], [3]]  (only ONE level removed)
}