how to take all string from left to right to given number in javascript 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: javascript get first 10 characters of string

var str = "Hello world That is reallly neat!";
var res = str.substring(0, 5);//get first 5 chars

Example 3: cut string from string javascript

var ret = "data-123".replace('data-','');
console.log(ret);   //prints: 123