js count certain characters in string code example

Example 1: how to count specific letters in string js

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

Example 2: javascript count character in string

var str = "Hello World!";
var n = str.length;