Revealing Module Pattern

[Welsh Harris]

Does anyone see any drawbacks to this pattern?

Similar to the revealing module pattern.  I like this because as I write my code everything is private.  Then when I'm done I decide what to make public.  Also, that last code block serves as a kind of documentation to quickly see what will be public.

var publicVar,

    privateVar;

    

publicVar = "Hello!";

privateVar = "Hidden";

function add(num1, num2) {

    return num1 + num2;

}

function subtract(num1, num2) {

    return runSubtract(num1, num2);

}

function runSubtract(num1, num2) {

    return num1 - num2;

}

//public

exports.add = add;

exports.subtract = subtract;

exports.publicVar = publicVar;

[Alexandre Morgaut]

You shouldn't use publicVar as a local variable if it is not an object or if it is not exposed as read-only

Primitive values are assigned to properties by copy while objects are by reference...

 

In your example, publicVar is only initialized by the module so you won't actually have a bug but it could have been safer to directly initialize exports.pubicVar to prevent issue once a contributor start to use publicVar internally instead of exports.publicVar

Otherwise, I like your pattern with a dedicated "export API" section, that I also happen to use

To fix the mentioned issue, you may move this section to the top. Because of hoisting, it would still work for your exposed functions, and primitive public values would be initialized directly in the right place

[Welsh Harris]

Ah!  Thanks Alexandre, makes sense.