Question

如何在Javascript中定义一个对象，使其主体包含属性，这些属性也是您定义的对象？例如，如果我正在定义一个名为有机体的类 - 并且任何有机体的定义包括另外两种称为生物体A和生物体B的生物体？是这样的：

Organism (){

value: value
Organism organismA; //microbe for example
Organism organismB; //bacteria for example

};

Answer 1

Javascript不是一种打字语言。

您无法强制执行对象属性的类型。如果你想要那样的话，看看像Typescript这样的东西。

您可以制作“嵌套对象”

var microbe = getMicrobe();
var bacteria = getBacteria();
var organism = { organismA: microbe,  organismB: bacteria };

但您无法强制执行其类型：

// not an error (until you try to use the property as an Organism)
organism.organismA = "Not an Organism";   
organism.organismB = 123; 

organism.doesntEvenExist = microbe;

Answer 2

如果您正在尝试创建一个构造函数，该构造函数将在实例上定义属性，这些属性也是对象的实例，那是不可能的。让我们举例说这是你的构造函数：

function Organism（）{ this.organismA = new Organism（）; }

然后尝试创建一个新实例会导致“RangeError：超出最大调用堆栈大小”，并且有充分理由，因为每次创建新实例时，它都会尝试自己创建一个新实例，因此直到你超过筹码。

但您可以在javascript中执行此操作：

function Organism () {}

var organism = new Organism();

organism.organismA = new Organism();
organism.organismB = new Organism();

// And now the instance and its properties are all Organism
console.log('organism is instance of Organism: ' + (organism instanceof Organism)); // true
console.log('organism.organismA is instance of Organism: ' + (organism.organismA instanceof Organism)); //true
console.log('organism.organismB is instance of Organism: ' + (organism.organismB instanceof Organism)); //true

// If you want you can wrap this in a factory

function createExtendedOrganism () {
  var organism = new Organism();

  organism.organismA = new Organism();
  organism.organismB = new Organism();
  
  return organism;

}

var extendedOrganism = createExtendedOrganism();

// Again the instance and its properties are all Organism
console.log('extendedOrganism is instance of Organism: ' + (extendedOrganism instanceof Organism)); //true
console.log('extendedOrganism.organismA is instance of Organism: ' + (extendedOrganism.organismA instanceof Organism)); //true
console.log('extendedOrganism.organismB is instance of Organism: ' + (extendedOrganism.organismB instanceof Organism)); //true

对象中的Javascript对象

2 个答案: