add hw2

node_modules/lodash-es/sortBy.js

@@ -0,0 +1,48 @@
+import baseFlatten from './_baseFlatten.js';
+import baseOrderBy from './_baseOrderBy.js';
+import baseRest from './_baseRest.js';
+import isIterateeCall from './_isIterateeCall.js';
+
+/**
+ * Creates an array of elements, sorted in ascending order by the results of
+ * running each element in a collection thru each iteratee. This method
+ * performs a stable sort, that is, it preserves the original sort order of
+ * equal elements. The iteratees are invoked with one argument: (value).
+ *
+ * @static
+ * @memberOf _
+ * @since 0.1.0
+ * @category Collection
+ * @param {Array|Object} collection The collection to iterate over.
+ * @param {...(Function|Function[])} [iteratees=[_.identity]]
+ *  The iteratees to sort by.
+ * @returns {Array} Returns the new sorted array.
+ * @example
+ *
+ * var users = [
+ *   { 'user': 'fred',   'age': 48 },
+ *   { 'user': 'barney', 'age': 36 },
+ *   { 'user': 'fred',   'age': 30 },
+ *   { 'user': 'barney', 'age': 34 }
+ * ];
+ *
+ * _.sortBy(users, [function(o) { return o.user; }]);
+ * // => objects for [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 30]]
+ *
+ * _.sortBy(users, ['user', 'age']);
+ * // => objects for [['barney', 34], ['barney', 36], ['fred', 30], ['fred', 48]]
+ */
+var sortBy = baseRest(function(collection, iteratees) {
+  if (collection == null) {
+    return [];
+  }
+  var length = iteratees.length;
+  if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {
+    iteratees = [];
+  } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {
+    iteratees = [iteratees[0]];
+  }
+  return baseOrderBy(collection, baseFlatten(iteratees, 1), []);
+});
+
+export default sortBy;