js how to get only the first letter code example

Example 1: js get first letter of string

var x = 'some string';
alert(x.charAt(0)); // alerts 's'

Example 2: js get words first letter

var str = "Java Script Object Notation";
var matches = str.match(/\b(\w)/g); // ['J','S','O','N']
var acronym = matches.join(''); // JSON

console.log(acronym)