add hw2

node_modules/lodash-es/isSymbol.js

@@ -0,0 +1,29 @@
+import baseGetTag from './_baseGetTag.js';
+import isObjectLike from './isObjectLike.js';
+
+/** `Object#toString` result references. */
+var symbolTag = '[object Symbol]';
+
+/**
+ * Checks if `value` is classified as a `Symbol` primitive or object.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Lang
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
+ * @example
+ *
+ * _.isSymbol(Symbol.iterator);
+ * // => true
+ *
+ * _.isSymbol('abc');
+ * // => false
+ */
+function isSymbol(value) {
+  return typeof value == 'symbol' ||
+    (isObjectLike(value) && baseGetTag(value) == symbolTag);
+}
+
+export default isSymbol;