add hw2

node_modules/lodash-es/_SetCache.js

@@ -0,0 +1,27 @@
+import MapCache from './_MapCache.js';
+import setCacheAdd from './_setCacheAdd.js';
+import setCacheHas from './_setCacheHas.js';
+
+/**
+ *
+ * Creates an array cache object to store unique values.
+ *
+ * @private
+ * @constructor
+ * @param {Array} [values] The values to cache.
+ */
+function SetCache(values) {
+  var index = -1,
+      length = values == null ? 0 : values.length;
+
+  this.__data__ = new MapCache;
+  while (++index < length) {
+    this.add(values[index]);
+  }
+}
+
+// Add methods to `SetCache`.
+SetCache.prototype.add = SetCache.prototype.push = setCacheAdd;
+SetCache.prototype.has = setCacheHas;
+
+export default SetCache;