add hw2

node_modules/lodash-es/isNumber.js

@@ -0,0 +1,38 @@
+import baseGetTag from './_baseGetTag.js';
+import isObjectLike from './isObjectLike.js';
+
+/** `Object#toString` result references. */
+var numberTag = '[object Number]';
+
+/**
+ * Checks if `value` is classified as a `Number` primitive or object.
+ *
+ * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are
+ * classified as numbers, use the `_.isFinite` method.
+ *
+ * @static
+ * @memberOf _
+ * @since 0.1.0
+ * @category Lang
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a number, else `false`.
+ * @example
+ *
+ * _.isNumber(3);
+ * // => true
+ *
+ * _.isNumber(Number.MIN_VALUE);
+ * // => true
+ *
+ * _.isNumber(Infinity);
+ * // => true
+ *
+ * _.isNumber('3');
+ * // => false
+ */
+function isNumber(value) {
+  return typeof value == 'number' ||
+    (isObjectLike(value) && baseGetTag(value) == numberTag);
+}
+
+export default isNumber;