Return a completely flattened version of an array.
let input = [ [ "a", "b" ], [ "c", "d" ], [ [ "double", "nested" ] ] ];flatten(input) // [ "a", "b", "c", "d", "double, "nested" ] Copy
let input = [ [ "a", "b" ], [ "c", "d" ], [ [ "double", "nested" ] ] ];flatten(input) // [ "a", "b", "c", "d", "double, "nested" ]
Return a completely flattened version of an array.
Example