length-of-last-word.js

/**
 * Source:  https://leetcode.com/problems/length-of-last-word/
 * Tags:    [String]
 * Level:   Easy
 * Updated: 2015-04-24
 * Title:   Length of Last Word
 * Auther:  @imcoddy
 * Content: Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.
 *
 * If the last word does not exist, return 0.
 *
 * Note: A word is defined as a character sequence consists of non-space characters only.
 *
 *
 * For example,
 * Given s = "Hello World",
 * return 5.
 */

/**
 * @param {string} s
 * @return {number}
 */

var lengthOfLastWord = function(s) {
    if (!s) {
        return 0;
    }
    s = s.trim();
    var last_space = s.lastIndexOf(' ');
    return s.length - (last_space+1);
};

console.log(lengthOfLastWord('This is a Test'));
console.log(lengthOfLastWord('A   '));
console.log(lengthOfLastWord());