concatenation javascript code example

Example 1: string concatenation in js

var str1 = "Hello ";
var str2 = "world!";
var res = str1.concat(str2);
console.log(res);

Example 2: 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 3: string concat javascript

//This method adds two or more strings and returns a new single string.

let str1 = new String( "This is string one" ); 
let str2 = new String( "This is string two" ); 
let str3 = str1.concat(str2.toString());
console.log("str1 + str2 : "+str3)

output:
str1 + str2 : This is string oneThis is string two

Example 4: js concatenate strings

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

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

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

Example 5: javascript string concatenation

var totn_string = '';

console.log(totn_string.concat('Tech','On','The','Net'));

//The following will be output to the web browser console log:

TechOnTheNet

Example 6: javascript concatenation

// the fastest way to string concat in cycle when number of string is less than 1e6
// see https://medium.com/@devchache/the-performance-of-javascript-string-concat-e52466ca2b3a
// see https://www.javaer101.com/en/article/2631962.html
function concat(arr) {
    let str = '';
    for (let i = 0; i < arr.length; i++) {
        str += arr[i];
    }

    return str;
}