add hw2

node_modules/lodash-es/flatMapDepth.js

@@ -0,0 +1,31 @@
+import baseFlatten from './_baseFlatten.js';
+import map from './map.js';
+import toInteger from './toInteger.js';
+
+/**
+ * This method is like `_.flatMap` except that it recursively flattens the
+ * mapped results up to `depth` times.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.7.0
+ * @category Collection
+ * @param {Array|Object} collection The collection to iterate over.
+ * @param {Function} [iteratee=_.identity] The function invoked per iteration.
+ * @param {number} [depth=1] The maximum recursion depth.
+ * @returns {Array} Returns the new flattened array.
+ * @example
+ *
+ * function duplicate(n) {
+ *   return [[[n, n]]];
+ * }
+ *
+ * _.flatMapDepth([1, 2], duplicate, 2);
+ * // => [[1, 1], [2, 2]]
+ */
+function flatMapDepth(collection, iteratee, depth) {
+  depth = depth === undefined ? 1 : toInteger(depth);
+  return baseFlatten(map(collection, iteratee), depth);
+}
+
+export default flatMapDepth;