Last Updated: February 25, 2016
·
288
· joseluisq

How assign default value to a param in a Javascript function: Basic

Defining a function

In this case true it's the default value.

function myfunction(param) {
   param = (param === undefined) ? true : param;
   return param;
}

Obviously you can define your own custom value.

Testing in console

For the first example the default value output is true

> myfunction();
  true

> myfunction("Hello world !");
  "Hello world !"

> myfunction("");
  ""

> myfunction(123456);
  123456

> myfunction(null);
  null

> myfunction(false);
  false

> myfunction(true);
  true