#2255 - Count Prefixes of a Given String

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Problem Description

You are given a string array words and a string s, where words[i] and s comprise only of lowercase English letters.

Return the number of strings in words that are a prefix of s.

A prefix of a string is a substring that occurs at the beginning of the string. A substring is a contiguous sequence of characters within a string.

Solution

/**
 * @param {string[]} words
 * @param {string} s
 * @return {number}
 */
var countPrefixes = function(words, s) {
  let result = 0;

  for (const word of words) {
    if (word.length <= s.length && s.startsWith(word)) {
      result++;
    }
  }

  return result;
};