Function flatten

Flattens nested arrays recursively with levels iterations.

Remarks

The verbose type signature comes from the recursive definition TypeScript uses for the built-in Array.flat().

Example

import * as A from "flurp/array";

const flattenOneLevel = A.flatten();
flattenOneLevel([[3, 4], [], [5, 6, 7, [8, 9]]]);  // [3, 4, 5, 6, 7, [8, 9]]

const flattenTwoLevels = A.flatten(2);
flattenTwoLevels([[3, 4], [], [5, 6, 7, [8, 9]]]);  // [3, 4, 5, 6, 7, 8, 9]