default parameters in node.js

Question

How does one go about setting default parameters in node.js?

For instance, let's say I have a function that would normally look like this:

function(anInt, aString, cb, aBool=true){    if(bool){...;}else{...;}    cb(); } 

To call it would look something like this:

function(1, 'no', function(){   ... }, false); 

or:

function(2, 'yes', function(){   ... }); 

However, it doesn't seem that node.js supports default parameters in this manner. What is the best way to acomplish above?

Answer 1

2017 answer: node 6 and above include ES6 default parameters

var sayMessage = function(message='This is a default message.') {   console.log(message); } 

Answer 2

Simplest solution is to say inside the function

var variable1 = typeof variable1  !== 'undefined' ?  variable1  : default_value; 

So this way, if user did not supply variable1, you replace it with default value.

In your case:

function(anInt, aString, cb, aBool) {   aBool = typeof aBool  !== 'undefined' ? aBool : true;   if(bool){...;}else{...;}   cb(); }