我习惯了Java中的经典OOP。
使用NodeJS在JavaScript中进行OOP的最佳实践是什么?
每个类都是一个包含module.export
的文件
如何创建类?
this.Class = function() {
//constructor?
var privateField = ""
this.publicField = ""
var privateMethod = function() {}
this.publicMethod = function() {}
}
vs. (我甚至不确定它是否正确)
this.Class = {
privateField: ""
, privateMethod: function() {}
, return {
publicField: ""
publicMethod: function() {}
}
}
与
this.Class = function() {}
this.Class.prototype.method = function(){}
...
继承是如何工作的?
在NodeJS中是否有用于实现OOP的特定模块?
我正在寻找上千种不同的方法来创建类似OOP的东西。但是我不知道什么是最常用/实用/干净的方法。
奖励问题:建议与MongooseJS一起使用的"OOP风格“是什么?(可以将MongooseJS文档视为类和用作实例的模型吗?)
编辑
这是一个用JsFiddle编写的例子,请提供反馈。
//http://javascriptissexy.com/oop-in-javascript-what-you-need-to-know/
function inheritPrototype(childObject, parentObject) {
var copyOfParent = Object.create(parentObject.prototype)
copyOfParent.constructor = childObject
childObject.prototype = copyOfParent
}
//example
function Canvas (id) {
this.id = id
this.shapes = {} //instead of array?
console.log("Canvas constructor called "+id)
}
Canvas.prototype = {
constructor: Canvas
, getId: function() {
return this.id
}
, getShape: function(shapeId) {
return this.shapes[shapeId]
}
, getShapes: function() {
return this.shapes
}
, addShape: function (shape) {
this.shapes[shape.getId()] = shape
}
, removeShape: function (shapeId) {
var shape = this.shapes[shapeId]
if (shape)
delete this.shapes[shapeId]
return shape
}
}
function Shape(id) {
this.id = id
this.size = { width: 0, height: 0 }
console.log("Shape constructor called "+id)
}
Shape.prototype = {
constructor: Shape
, getId: function() {
return this.id
}
, getSize: function() {
return this.size
}
, setSize: function (size) {
this.size = size
}
}
//inheritance
function Square(id, otherSuff) {
Shape.call(this, id) //same as Shape.prototype.constructor.apply( this, arguments ); ?
this.stuff = otherSuff
console.log("Square constructor called "+id)
}
inheritPrototype(Square, Shape)
Square.prototype.getSize = function() { //override
return this.size.width
}
function ComplexShape(id) {
Shape.call(this, id)
this.frame = null
console.log("ComplexShape constructor called "+id)
}
inheritPrototype(ComplexShape, Shape)
ComplexShape.prototype.getFrame = function() {
return this.frame
}
ComplexShape.prototype.setFrame = function(frame) {
this.frame = frame
}
function Frame(id) {
this.id = id
this.length = 0
}
Frame.prototype = {
constructor: Frame
, getId: function() {
return this.id
}
, getLength: function() {
return this.length
}
, setLength: function (length) {
this.length = length
}
}
/////run
var aCanvas = new Canvas("c1")
var anotherCanvas = new Canvas("c2")
console.log("aCanvas: "+ aCanvas.getId())
var aSquare = new Square("s1", {})
aSquare.setSize({ width: 100, height: 100})
console.log("square overridden size: "+aSquare.getSize())
var aComplexShape = new ComplexShape("supercomplex")
var aFrame = new Frame("f1")
aComplexShape.setFrame(aFrame)
console.log(aComplexShape.getFrame())
aCanvas.addShape(aSquare)
aCanvas.addShape(aComplexShape)
console.log("Shapes in aCanvas: "+Object.keys(aCanvas.getShapes()).length)
anotherCanvas.addShape(aCanvas.removeShape("supercomplex"))
console.log("Shapes in aCanvas: "+Object.keys(aCanvas.getShapes()).length)
console.log("Shapes in anotherCanvas: "+Object.keys(anotherCanvas.getShapes()).length)
console.log(aSquare instanceof Shape)
console.log(aComplexShape instanceof Shape)
发布于 2013-08-12 21:26:41
这是一个开箱即用的例子。如果你想要少一些"hacky",你应该使用继承库或者类似的库。
在animal.js文件中,你可以这样写:
var method = Animal.prototype;
function Animal(age) {
this._age = age;
}
method.getAge = function() {
return this._age;
};
module.exports = Animal;
要在其他文件中使用它:
var Animal = require("./animal.js");
var john = new Animal(3);
如果你想要一个“子类”,那么在mouse.js中:
var _super = require("./animal.js").prototype,
method = Mouse.prototype = Object.create( _super );
method.constructor = Mouse;
function Mouse() {
_super.constructor.apply( this, arguments );
}
//Pointless override to show super calls
//note that for performance (e.g. inlining the below is impossible)
//you should do
//method.$getAge = _super.getAge;
//and then use this.$getAge() instead of super()
method.getAge = function() {
return _super.getAge.call(this);
};
module.exports = Mouse;
你也可以考虑“方法借用”而不是垂直继承。你不需要继承一个“类”来在你的类上使用它的方法。例如:
var method = List.prototype;
function List() {
}
method.add = Array.prototype.push;
...
var a = new List();
a.add(3);
console.log(a[0]) //3;
发布于 2016-01-18 11:57:37
作为Node.js社区,确保来自JavaScript ECMA-262规范的新功能及时带给Node.js开发人员。
您可以查看JavaScript classes。在JavaScript6的Javascript类中引入了MDN link to JS classes ,这种方法提供了在JavaScript中建模OOP概念的更简单的方法。
注意::JS类只能在严格模式中工作。
下面是一些用Node.js (使用Node.js Version v5.0.0 )编写的类和继承的框架。
类声明:
'use strict';
class Animal{
constructor(name){
this.name = name ;
}
print(){
console.log('Name is :'+ this.name);
}
}
var a1 = new Animal('Dog');
继承:
'use strict';
class Base{
constructor(){
}
// methods definitions go here
}
class Child extends Base{
// methods definitions go here
print(){
}
}
var childObj = new Child();
发布于 2013-08-12 21:30:05
我建议使用标准util
模块附带的inherits
助手:http://nodejs.org/api/util.html#util_util_inherits_constructor_superconstructor
下面是一个如何在链接页面上使用它的示例。
https://stackoverflow.com/questions/18188083
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