javascript extract from string code example

Example 1: how to get the first character of a string in javascript

let str = 'John Wick'
let firstChar = str.charAt(0) 
console.log(firstChar); // "J"

Example 2: substring javascript

var str = "Hello world!";
var res = str.substring(1, 4); //ell

Example 3: str.substring if 2 letters

public String firstTwo(String str) {
    return str.length() < 2 ? str : str.substring(0, 2);
}