Count the number of occurrences of a character in a string in Javascript

Question

I need to count the number of occurrences of a character in a string.

For example, suppose my string contains:

var mainStr = \"str1,str2,str3,str4\";         


        

Answer 1

Here is a similar solution, but it uses Array.prototype.reduce

function countCharacters(char, string) {
  return string.split('').reduce((acc, ch) => ch === char ? acc + 1: acc, 0)
}

As was mentioned, String.prototype.split works much faster than String.prototype.replace.