join two strings in js code example

Example 1: how to concatenate strings javascript

var str1 = "Hello ";
var str2 = "world!";
var res = str1.concat(str2);
// does not change the existing strings, but
// returns a new string containing the text
// of the joined strings.

Example 2: how to concatenate a string in javascript

let first_string = 'I am a programmer, ';
let second_string = 'I am indisposable.';
let what_i_said  = first_string + second_string;
console.log(what_i_said);

/* OR 
*/

let tell_my_boss = first_string.concat(second_string);
console.log(tell_my_boss);