我正在阅读有关
mixin pattern in javascript的内容,我遇到了一段我不理解的代码：
SuperHero.prototype = Object.create( Person.prototype );
原始代码中实际上存在拼写错误(大写字母H).如果我将它包装下来就可以了.但是,如果我实际删除该行,一切似乎都是一样的.
这是完整的代码：
var Person = function( firstName,lastName ){
this.firstName = firstName;
this.lastName = lastName;
this.gender = "male";
};
// a new instance of Person can then easily be created as follows:
var clark = new Person( "Clark","Kent" );
// Define a subclass constructor for for "Superhero":
var Superhero = function( firstName,lastName,powers ){
// Invoke the superclass constructor on the new object
// then use .call() to invoke the constructor as a method of
// the object to be initialized.
Person.call( this,firstName,lastName );
// Finally,store their powers,a new array of traits not found in a normal "Person"
this.powers = powers;
};
SuperHero.prototype = Object.create( Person.prototype );
var superman = new Superhero( "Clark","Kent",["flight","heat-vision"] );
console.log( superman );
// Outputs Person attributes as well as powers
什么SuperHero.prototype = Object.create(Person.prototype);做？
解决方法
它创建了一个从Person构造函数的原型对象继承的新对象.
就像你这样做一样.
SuperHero.prototype = new Person();
除了它创建Person实例而不实际调用Person构造函数中的代码.
此对象用作SuperHero构造函数的原型对象,因此在创建SuperHero实例时,它将继承Person的所有原型属性,以及直接添加到SuperHero原型对象的任何原型属性.