concatenate string and int in javascript code example

Example 1: concantene number in js

Use "" + 5 + 6 to force it to strings. 
This works with numerical variables too:

var a = 5;
var b = 6;
console.log("" + a + b);

Example 2: js concatenate strings

const str1 = 'Hello';
const str2 = 'World';

console.log(str1 + str2);
>> HelloWorld

console.log(str1 + ' ' + str2);
>> Hello World