我构建了一个在Node JS中使用多态的代码。item，projectModule和testCase是businessComponent，我<sub-class>.prototype.create.itemType是我的超类; s子类。在我的例子中，除文件读取操作外，每个操作都是相同的。因此，我使用create()创建了具有var test = new projectModule();
test.create();
函数的唯一新变量。当我打电话
create functions is called控制台记录文本item表示使用itemType原型成功但代码无法正常工作，因为undefined为itemType。如何使用var item = function () {};
item.prototype.create = function () {
console.log('create functions is called');
if(itemType==='module')
console.log('read module json');
if(itemType==='tc')
console.log('read tc json');
if(itemType==='bc')
console.log('read bc json');
}
var projectModule = function () {};
projectModule.prototype = Object.create(item.prototype);
projectModule.prototype.create.itemType = 'module';
var testCase = function () {};
testCase.prototype = Object.create(item.prototype);
testCase.prototype.create.itemType = 'tc';
var businessComponent = function () {};
businessComponent.prototype = Object.create(item.prototype);
businessComponent.prototype.create.itemType = 'bc';
//call the function
var test = new projectModule();
test.create();
变量？
na.action = NULL答案 0 :(得分：1)
看起来您需要有关原型继承如何在javascript中工作的信息。
您要找的是关键字this。
从here
中提取的示例代码function Plant () {
this.country = "Mexico";
this.isOrganic = true;
}
// Add the showNameAndColor method to the Plant prototype property
Plant.prototype.showNameAndColor = function () {
console.log("I am a " + this.name + " and my color is " + this.color);
}
// Add the amIOrganic method to the Plant prototype property
Plant.prototype.amIOrganic = function () {
if (this.isOrganic)
console.log("I am organic, Baby!");
}
function Fruit (fruitName, fruitColor) {
this.name = fruitName;
this.color = fruitColor;
}
// Set the Fruit's prototype to Plant's constructor, thus inheriting all of Plant.prototype methods and properties.
Fruit.prototype = new Plant ();
// Creates a new object, aBanana, with the Fruit constructor
var aBanana = new Fruit ("Banana", "Yellow");
// Here, aBanana uses the name property from the aBanana object prototype, which is Fruit.prototype:
console.log(aBanana.name); // Banana
// Uses the showNameAndColor method from the Fruit object prototype, which is Plant.prototype. The aBanana object inherits all the properties and methods from both the Plant and Fruit functions.
console.log(aBanana.showNameAndColor()); // I am a Banana and my color is yellow.