30-seconds-of-code/snippets/countSubstrings.md

title, tags, firstSeen, lastUpdated

title	tags	firstSeen	lastUpdated
countSubstrings	string,algorithm,beginner	2020-12-31T13:58:51+02:00	2021-01-08T00:23:44+02:00

Counts the occurrences of a substring in a given string.

• Use Array.prototype.indexOf() to look for searchValue in str.
• Increment a counter if the value is found and update the index, i.
• Use a while loop that will return as soon as the value returned from Array.prototype.indexOf() is -1.

const countSubstrings = (str, searchValue) => {
  let count = 0,
    i = 0;
  while (true) {
    const r = str.indexOf(searchValue, i);
    if (r !== -1) [count, i] = [count + 1, r + 1];
    else return count;
  }
};

countSubstrings('tiktok tok tok tik tok tik', 'tik'); // 3
countSubstrings('tutut tut tut', 'tut'); // 4