javascript append to string code example

Example 1: javascript add string to middle of string

function addStr(str, index, stringToAdd){
  return str.substring(0, index) + stringToAdd + str.substring(index, str.length);
}

let str = "This is a string";
let stringToAdd = "modyfied ";

console.log(addStr(str, 10, stringToAdd));  //outPut : "This is a modified string"

Example 2: string concatenation in js

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

Example 3: 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 4: 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 5: javascript string concat vs +

It is strongly recommended to use the string
concatenationoperators (+, +=) instead of String.concat
method for perfomance reasons

Example 6: 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