Function baseFlatten

lodash.js:2980–3001

* The base implementation of `_.flatten` with support for restricting flattening. * * @private * @param {Array} array The array to flatten. * @param {number} depth The maximum recursion depth. * @param {boolean} [predicate=isFlattenable] The function invoked per iteration.

(array, depth, predicate, isStrict, result)

     * @returns {Array} Returns the new flattened array.
     */
    function baseFlatten(array, depth, predicate, isStrict, result) {
      var index = -1,
          length = array.length;

      predicate || (predicate = isFlattenable);
      result || (result = []);

      while (++index < length) {
        var value = array[index];
        if (depth > 0 && predicate(value)) {
          if (depth > 1) {
            // Recursively flatten arrays (susceptible to call stack limits).
            baseFlatten(value, depth - 1, predicate, isStrict, result);
          } else {
            arrayPush(result, value);
          }
        } else if (!isStrict) {
          result[result.length] = value;
        }
      }
      return result;
    }

    /**
     * The base implementation of `baseForOwn` which iterates over `object`