What is the correct way to concatenate strings in Javascript?

Question

I started learning Python and was told that I shouldn’t concatenate the strings with , but use the method .format(). And in Javascript it is correct to use + or , to concatenate the strings or there is a more recommended and more used way?

Answer 1

You can also use "template string" for this:

var str1 = 'hello';
var str2 = 'world';
var res = `${str1} ${str2}`;

In this case where there are only 2 strings, it doesn’t make much sense to use, but in larger concretions, it is very interesting.

Template string is part of ES6/ES2015, some older browsers may not support.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/template_strings http://wesbos.com/javascript-template-strings/

Answer 2

There’s nothing ugly or wrong in making a simple str1+" "+str2. It can be used without problems. It is simple and efficient. It has no technical reasons to choose a shape, it is just style.

Although ugly depends on taste, I find any other ugly form, longer and even less intuitive when it strikes the eye fast. Pick one and be consistent, don’t keep changing the shape.

There could be problems if you make many concatenations within a loop, but even this JS optimizes, so up to the use of str += str2 is fitting in a loop.

Answer 3

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

Upshot: Hello world!

Reference: https://www.w3schools.com/JSREF/jsref_concat_string.asp

Another way, with +:

var res = str1+str2;