add: 最后一个单词的长度

src/string/length-of-last-word.js

@@ -0,0 +1,10 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+export const lengthOfLastWord = function (s) {
+  s = s.trim()
+  const tmp = s.lastIndexOf(' ')
+  const lastWord = s.substring(tmp === -1 ? 0 : tmp + 1, s.length)
+  return lastWord.length
+}