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- var arrayPush = require('./_arrayPush'),
- isFlattenable = require('./_isFlattenable');
-
- /**
- * 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.
- * @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
- * @param {Array} [result=[]] The initial result value.
- * @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;
- }
-
- module.exports = baseFlatten;
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