freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/rosetta-code/count-occurrences-of-a-substring.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
596fda99c69f779975a1b67d	Count occurrences of a substring	5	302237	count-occurrences-of-a-substring

--description--

Create a function, or show a built-in function, to count the number of non-overlapping occurrences of a substring inside a string.

The function should take two arguments:

• the first argument being the string to search, and
• the second a substring to be searched for.

It should return an integer count.

The matching should yield the highest number of non-overlapping matches.

In general, this essentially means matching from left-to-right or right-to-left.

--hints--

countSubstring should be a function.

assert(typeof countSubstring === 'function');

countSubstring("the three truths", "th") should return 3.

assert.equal(countSubstring(testCases[0], searchString[0]), results[0]);

countSubstring("ababababab", "abab") should return 2.

assert.equal(countSubstring(testCases[1], searchString[1]), results[1]);

countSubstring("abaabba*bbaba*bbab", "a*b") should return 2.

assert.equal(countSubstring(testCases[2], searchString[2]), results[2]);

--seed--

--after-user-code--

const testCases = ['the three truths', 'ababababab', 'abaabba*bbaba*bbab'];
const searchString = ['th', 'abab', 'a*b'];
const results = [3, 2, 2];

--seed-contents--

function countSubstring(str, subStr) {

  return true;
}

--solutions--

function countSubstring(str, subStr) {
  const escapedSubStr = subStr.replace(/[.+*?^$[\]{}()|/]/g, '\\$&');
  const matches = str.match(new RegExp(escapedSubStr, 'g'));
  return matches ? matches.length : 0;
}