Question

在俄罗斯维基百科上，我找到了Builder设计模式的代码，并尝试将其转换为coffeescript。 Builder.js

的要点

// Abstract Builder
function PizzaBuilder() {
    var pizza = new Pizza();
    this.getPizza = function() {
        return pizza;
    };
    this.createNewPizzaProduct = function() {
        pizza.clear();
    };
    this.buildDough = function(val) { };
    this.buildSauce = function(val) { };
    this.buildTopping = function(val) { };
}
// ConcreteBuilder
function HawaiianPizzaBuilder() {
    PizzaBuilder.call(this);
    var pizza = this.getPizza(); // imitation protected
    this.buildDough = function() { pizza.setDough("cross"); };
    this.buildSauce = function() { pizza.setSauce("mild"); };
    this.buildTopping = function() { pizza.setTopping("ham+pineapple"); };
}

我将构造函数调用的每个函数（新的FuncName）都更改为class FuncName，但构造函数中的PizzaBuilder.call(this);发生了错误。

PizzaBuilder = ->
    pizza = new Pizza()
    @getPizza = -> pizza
    @createNewPizzaProduct = -> pizza.clear()
    @buildDough = (val) ->
    @buildSauce = (val) ->
    @buildTopping = (val) ->

class HawaiianPizzaBuilder
    PizzaBuilder.call this
    pizza = @getPizza() # imitation protected
    buildDough: -> pizza.setDough "cross"
    buildSauce: -> pizza.setSauce "mild"
    buildTopping: -> pizza.setTopping "ham+pineapple"

Answer 1

在javascript函数中HawaiianPizzaBuilder是类的构造函数。在Coffeescript中，您需要将其明确定义为constructor方法，这样：

class HawaiianPizzaBuilder
    constructor: ->
       PizzaBuilder.call this
       pizza = @getPizza() # imitation protected
       @buildDough: -> pizza.setDough "cross"
       @buildSauce: -> pizza.setSauce "mild"
       @buildTopping: -> pizza.setTopping "ham+pineapple"

您在this.函数定义之前忘记了build...。

但是我想建议另一个版本相同的模式示例，因为coffeescript提供了更简单的类继承语法，类似于：

class PizzaBuilder
    constructor: ->
        @pizza = new Pizza()
    buildDough: -> @
    buildSauce: -> @
    buildTopping: -> @

class HawaiianPizzaBuilder
    buildDough: -> 
        @pizze.setDough "cross"
        @
    #...override other methods


 builder = new HawaiianPizzaBuilder
 myPizza = builder.buildDough().buildSauce().pizza

将JS设计模式转换为CoffeeScript发生了类错误

1 个答案: