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

You can also rest your string and work with it like an array of elements using

• Array.prototype.filter()

const mainStr = 'str1,str2,str3,str4';
const commas = [...mainStr].filter(l => l === ',').length;

console.log(commas);

Or

• Array.prototype.reduce()

const mainStr = 'str1,str2,str3,str4';
const commas = [...mainStr].reduce((a, c) => c === ',' ? ++a : a, 0);

console.log(commas);