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