What is exports and prototype in Javascript?

Question

I am new to Javascript and am seeing a lot of usage of exports and prototype in the code that I read. What are they mainly used for and how do they work?

//from express
var Server = exports = module.exports = function HTTPSServer(options, middleware){
  connect.HTTPSServer.call(this, options, []);
  this.init(middleware);
};

Server.prototype.__proto__ = connect.HTTPSServer.prototype;

`export` keyword details [here](https://developer.mozilla.org/en/docs/web/javascript/reference/statements/export). Currently it is not supported natively by any of the web-browsers. — RBT, May 01 '17 at 06:42

score 23 · Answer 1 · edited Oct 24 '15 at 21:46

23

Exports is used to make parts of your module available to scripts outside the module. So when someone uses require like below in another script:

var sys = require("sys");

They can access any functions or properties you put in module.exports

The easiest way to understand prototype in your example is that Server is a class that inherits all of the methods of HTTPSServer. prototype is one way to achieve class inheritance in javascript.

edited Oct 24 '15 at 21:46

nbro

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answered Mar 21 '11 at 16:03

Tom Gruner

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but note that export, and modules in general, is not plain javascript, but an "extention" of node.js – Yannick Loiseau Mar 21 '11 at 16:06
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Years went by and now it is a CommonJS modules pattern, not only for Node but in many other JavaScript environments. Including the browser thanks to polyfills and soon enough ES6 (the next JavaScript version) – Ivan Castellanos Jan 04 '14 at 01:25
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@Yannick Loiseau `module` is `node` keyword And `export` is `javascript` keyword [javascript keyword list](http://www.w3schools.com/js/js_reserved.asp) – vijay Jan 18 '15 at 17:30
"is one way to achieve class inheritance in javascript." Are there more? – Ricardo May 31 '16 at 11:18

score 13 · Answer 2 · edited Feb 02 '17 at 21:29

13

This video explains node.js module.exports and here is a resource which describes JavaScript prototype.

edited Feb 02 '17 at 21:29

ruffin

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answered Mar 21 '11 at 16:08

yojimbo87

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Thanks! That video was extremely helpful as well as the link. – Kiran Ryali Mar 24 '11 at 19:39
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The video link is now longer valid. I believe it is now: http://nodetuts.com/05-modules.html – Jim Rush Nov 09 '14 at 13:12
Please fix the first link! – nbro Oct 24 '15 at 21:46
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@JimRush Those responsible for sacking the people who have just been sacked because of a broken link have been sacked. Is the one there now what you expected? – ruffin Feb 02 '17 at 21:32

What is exports and prototype in Javascript?

2 Answers2

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