add hw2

node_modules/lodash-es/snakeCase.js

@@ -0,0 +1,28 @@
+import createCompounder from './_createCompounder.js';
+
+/**
+ * Converts `string` to
+ * [snake case](https://en.wikipedia.org/wiki/Snake_case).
+ *
+ * @static
+ * @memberOf _
+ * @since 3.0.0
+ * @category String
+ * @param {string} [string=''] The string to convert.
+ * @returns {string} Returns the snake cased string.
+ * @example
+ *
+ * _.snakeCase('Foo Bar');
+ * // => 'foo_bar'
+ *
+ * _.snakeCase('fooBar');
+ * // => 'foo_bar'
+ *
+ * _.snakeCase('--FOO-BAR--');
+ * // => 'foo_bar'
+ */
+var snakeCase = createCompounder(function(result, word, index) {
+  return result + (index ? '_' : '') + word.toLowerCase();
+});
+
+export default snakeCase;