add hw2

node_modules/lodash/_createSet.js

@@ -0,0 +1,19 @@
+var Set = require('./_Set'),
+    noop = require('./noop'),
+    setToArray = require('./_setToArray');
+
+/** Used as references for various `Number` constants. */
+var INFINITY = 1 / 0;
+
+/**
+ * Creates a set object of `values`.
+ *
+ * @private
+ * @param {Array} values The values to add to the set.
+ * @returns {Object} Returns the new set.
+ */
+var createSet = !(Set && (1 / setToArray(new Set([,-0]))[1]) == INFINITY) ? noop : function(values) {
+  return new Set(values);
+};
+
+module.exports = createSet;