NodeJS Exports–exports vs Module.exports

Original:http://www.hacksparrow.com/node-js-exports-vs-module-exports.html

Reference:http://www.cnblogs.com/kongxianghai/p/3936197.html

1. exports object in the Nodejs module: You can use it to create your module. For example:

Suppose this is a rocker.js file:

# Rocker.js

Exports.name = function () {    console.log (' My name is Lemmy Kilmister ');};

Then, in another file, you can refer to this:

var rocker = require ('./rocker.js ');
Rocker.name ();    ' My name is Lemmy Kilmister '

Emphasize:

(1) Assigning a value to a exports is actually adding properties to the empty object of module.exports, eg:

var name = ' NSWBMW '; Exports.name = name; Exports.sayname = function () {  
Module.exports.sayName = function () {  console.log (name);}

(2) The use of the two different methods, eg:

Using exports:

# Circle.js--Define a method with exports
Exports.area = function (r) {  

# App.js--using the method defined in the above file

Console.log (Circle.area (4));    # Use, reference way : ***.area ()

Using Module.exports:

# Area.js--Define method using Module.exports
Module.exports = function (r) {  return R * R * MATH.PI;  

Console.log (Area (4));  # Direct Use , * * * ()

2. Module.exports :

• Module.exports is the real interface, exports is just one of its auxiliary tools.
• The final return to the call is module.exports instead of exports.
• All the properties and methods collected by the exports are assigned to Module.exports. Of course, there is a premise that the module.exports itself does not have any attributes or methods. If Module.exports already has some properties and methods, the information collected by exports will be ignored. Eg: Modify Rocker.js as follows:

  # Modified Rocker.js
  ' ROCK It! ' ;   = function () {     console.log ('My name is Lemmy Kilmister'
  

  At this point, the execution rocker.js is referenced again as follows:

  var rocker = require ('./rocker.js ');
  //
  # Found Error: Object "ROCK it!" No Name method

  The rocker module ignores the name method collected by exports and returns a string "ROCK it!". Your module does not necessarily have to return "instanced objects". Your module can be any legitimate JavaScript object--boolean, number, date, JSON, string, function, array, and so on.

• Your module can be anything you set to it. If you do not explicitly Module.exports  set any properties and methods, then your module is exports set toModule.exports 的属性。

  eg1: 你的模块是一个类：

# Modify Rocker.js again
Module.exports = function (name, age) {    this.name = name;    This.age = age;    This.about = function () {        console.log (this.name + ' is ' + this.age + ' years old ');};    };

You can use it this way:

var rocker = require ('./rocker.js ');
var r = new Rocker (' Ozzy ', 62);
R.about ();   Ozzy is years old

eg2: 你的模块是一个数组：

# Modify Rocker.js again

Module.exports = [' Lemmy Kilmister ', ' Ozzy Osbourne ', ' Ronnie James Dio ', ' Steven Tyler ', ' Mick Jagger '];

You can use it this way:

var rocker = require ('./rocker.js ');
Console.log (' Rockin in Heaven: ' + rocker[2]); Rockin in Heaven:ronnie James Dio

Now you understand that if you want your module to be a specific type to use Module.exports，直接 变量/new方法 使用 . If you want the module to be a typical "instanced object" , use exports to reference the. * * *.

• Adding a property to Module.exports is similar to adding a property to exports. For example:

  Module.exports.name = function () {    console.log ('My name is Lemmy Kilmister' );};

  Again, exports is like this:

  Exports.name = function () {    console.log ('My name is Lemmy Kilmister'  );};

  Emphasis: These two definitions do not work the same (I am still a little dizzy, follow-up will continue to learn). As mentioned earlier, Module.exports is a true interface, and exports is nothing more than an auxiliary tool. It is recommended to export using exports unless you intend to change from the original "Instanced object" to a type!!

NodeJS Exports–exports vs Module.exports