add: 左旋转字符串

src/string/zuo-xuan-zhuan-zi-fu-chuan-lcof.js

@@ -0,0 +1,8 @@
+/**
+ * @param {string} s
+ * @param {number} n
+ * @return {string}
+ */
+export const reverseLeftWords = function (s, n) {
+  return (s + s).substr(n, s.length)
+}