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.var str1 = "Hello ";
var str2 = "world!";
var res = str1.concat(str2);
console.log(res);//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 twoconst str1 = 'Hello';
const str2 = 'World';
console.log(str1.concat(' ', str2));
// expected output: "Hello World"
console.log(str2.concat(', ', str1));
// expected output: "World, Hello"It is strongly recommended to use the string
concatenationoperators (+, +=) instead of String.concat
method for perfomance reasonsvar arr = [1, 2, 3, 4];
var arr2 = [5, 6, 7, 8];
const both = arr.concat(arr2);
console.log(both);
//[1, 2, 3, 4, 5, 6, 7, 8]