JavaScript編程設(shè)計模式之構(gòu)造器模式實例分析

//1, 推薦使用
var newObject = {};
//2,
var newObject = Object.create( null );
//3, 不推薦
var newObject = new Object();

// ECMAScript 3 兼容的方式
// 1. 常規(guī)對象定義方式
//設(shè)置屬性
newObject.someKey = "Hello World";
//獲取屬性
var key = newObject.someKey;
// 2. 方括號方式
// 設(shè)置屬性
newObject["someKey"] = "Hello World";
//獲取屬性
var key = newObject["someKey"];
// 僅僅用于ECMAScript 5
// 3. Object.defineProperty
// 設(shè)置屬性
Object.defineProperty(
 newObject, "someKey",
 { value: "for more control of the property's behavior",
  writable: true,
  enumerable: true,
  configurable: true
});
//可以通過下面的函數(shù)簡化屬性設(shè)置
var defineProp = function ( obj, key, value ){
  config.value = value;
  Object.defineProperty( obj, key, config );
};
// 使用方法
var person = Object.create( null );defineProp( person, "car", "Delorean" );
defineProp( person, "dateOfBirth", "1981" );
defineProp( person, "hasBeard", false );
// 4. Object.defineProperties
//設(shè)置屬性
Object.defineProperties(
newObject,
{ "someKey": { value: "Hello World", writable: true },
 "anotherKey": { value: "Foo bar", writable: false }
});
// 3和4的獲取屬性方法同1,2.

function Car( model, year, miles ) {
  //這里，this指向新建立的對象自己
  this.model = model;
  this.year = year;
  this.miles = miles;
  this.toString = function () {
    return this.model + " has done " + this.miles + " miles";
  };
}
//用法
// 建立兩個car實例
var civic = new Car( "Honda Civic", 2009, 20000 );
var mondeo = new Car( "Ford Mondeo", 2010, 5000 );
// 輸出結(jié)果
console.log( civic.toString() );
console.log( mondeo.toString() );

function Car( model, year, miles ) {
  this.model = model;
  this.year = year;
  this.miles = miles;
}
Car.prototype.toString = function () {
  return this.model + " has done " + this.miles + " miles";
};
// 用法
var civic = new Car( "Honda Civic", 2009, 20000 );
var mondeo = new Car( "Ford Mondeo", 2010, 5000 );
//輸出
console.log( civic.toString() );
console.log( mondeo.toString() );