get first 100 characters string in js code example

Example 1: str.substring if 2 letters

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

Example 2: reactjs cut part of string

var str = "Hello world!";

var res = str.substring(1, 4);

// res value is "ell"