#28 - Implement strStr()

Easy • View on LeetCode • View on GitHub

Problem Description

Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.

Clarification:

What should we return when needle is an empty string? This is a great question to ask during an interview.
For the purpose of this problem, we will return 0 when needle is an empty string. This is consistent to C's strstr() and Java's indexOf().

Solution

/**
 * @param {string} haystack
 * @param {string} needle
 * @return {number}
 */
var strStr = function(haystack, needle) {
  if (!needle) return 0;
  const split = haystack.split(needle);
  return split.length > 1 ? split[0].length : -1;
};