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";

I want to find the count of comma , character, which is 3. And the count of individual strings after the split along comma, which is 4.

I also need to validate that each of the strings i.e str1 or str2 or str3 or str4 should not exceed, say, 15 characters.

Answer 1

I have updated this answer. I like the idea of using a match better, but it is slower:

console.log(("str1,str2,str3,str4".match(/,/g) || []).length); //logs 3

console.log(("str1,str2,str3,str4".match(new RegExp("str", "g")) || []).length); //logs 4