Question

如何扩展此范围以便以下工作？我尝试过使用.bind（）函数，但似乎无法使用任何东西。

var myObj = {
   test: "Hello",
   test2: " World",
   run: {
      all: function() {
         return this.test + this.test2;
      },
      part: function() {
         return this.test2;
      }
   }
}
console.log(myObj.run.all())
// => "Hello World"
console.log(myObj.run.part())
// => " World"

Answer 1

函数all和part是对象run的成员，run没有值test和test2。它们是myObj的成员对象。

您可以将this关键字替换为myObj。

var myObj = {
   test: "Hello",
   test2: " World",
   run: {
      all: function() {
         return myObj.test + myObj.test2;
      },
      part: function() {
         return myObj.test2;
      }
   }
}
console.log(myObj.run.all())
console.log(myObj.run.part())

Answer 2

我最近遇到了同样的问题。我通过使用函数

解决了

var myObj = function(){
   var self = this;
   this.test = "Hello";
   this.test2 = " World";
   this.run = {
      all: function() {
         return self.test + self.test2;
      },
      part: function() {
         return self.test2;
      }
   }
}
console.log(myObj.run.all())
// => "Hello World"
console.log(myObj.run.part())
// => " World"

我还发现 bind 可以完成工作！

var myObj = {
   test: "Hello",
   test2: " World",
   run: {
      all: function() {
         return this.test + this.test2;
      },
      part: function() {
         return this.test2;
      }
   }
};

console.log( myObj.run.all.bind(myObj)() );
// => "Hello World"
console.log( myObj.run.part.bind(myObj)() );
// => "World"

工作小提琴==＆gt; https://jsfiddle.net/sn5w7872/

Answer 3

使用apply

#change the value in return to set the single color need, in hsl format. def grey_color_func(word, font_size, position,orientation,random_state=None, **kwargs): return("hsl(230,100%%, %d%%)" % np.random.randint(49,51)) #create the wordcloud object wordcloud = WordCloud(background_color='white',max_font_size = 50).generate(tmp) #change the color setting wordcloud.recolor(color_func = grey_color_func)方法调用具有给定apply()值的函数，并将参数作为数组提供

this

Answer 4

使用ES6类和箭头函数。

class myObj {
    constructor() {
        this.test = "Hello";
        this.test2 = " World";
        this.run = {
            all: () => this.test + this.test2,
            part: () => this.test2
        }
    }
}

var obj = new myObj();
console.log(obj.run.all())
// => "Hello World"
console.log(obj.run.part())
// => " World"

这是工作小提琴 - https://jsfiddle.net/sgsvenkatesh/vn9b1f95/

如何扩大这个范围

4 个答案: