Question

我想知道为什么我无法访问参数＆＃39; this.name＆＃39;在方法的装饰者中。

我的代码：

＆＃13;

class A {
  name: string;

  construct() {
    this.name = 'test';
  }

  @decorators(this.name)
  method() {}
}

＆＃13;

在我的装饰师中，我得到一个未定义的。我错过了一些东西，我没有得到它。你能救我吗？谢谢

Answer 1

您从对象语法开始：var C = { name: string; } 我为您创建了一个代码片段，用于创建类并使用extend函数。在评论中询问ES5的解释。

class A {
  constructor(param1, param2) {
    this.param1 = param1;
    this.param2 = param2;
  }
  
  // create a function
  get1() {
    return this.param1
  }
  
  set1(param1) {
    this.param1 = param1;
  }
}

class B extends A {
  constructor(param1, param2, param3) {
    super(param1, param2); // Call A's constructor via super
    this.param3 = param3;
  }
  
  get3() {
    return this.param3
  }
  
  set3(param3) {
    this.param3 = param3;
  }
}

let a = new A(10, "foo"),
    b = new B(5, "doo", "lala");

console.log("--- A ---");

console.log("a.get1() : " + a.get1()); // read date from a
a.set1(3); // set a.param1 to 3
console.log("a.get1() : " + a.get1()); // read date from a

console.log("a.param2 : " + a.param2); // read date from a
a.param2 = 15; // set a.param2 to 15
console.log("a.param2 : " + a.param2); // read date from a

// add a variable to the a object
a.newvar = "new variable a";
console.log(a.newvar);

// add a function to the a object
a.newfunc = (param) => {
  return param;
}
console.log(a.newfunc("function a"));

console.log("--- B ---");

console.log("b.get1() : " + b.get1()); // read date from b
b.set1(3); // set b.param1 to 3
console.log("b.get1() : " + b.get1()); // read date from b

console.log("b.param2 : " + b.param2); // read date from b
b.param2 = 15; // set b.param2 to 15
console.log("b.param2 : " + b.param2); // read date from b

console.log("b.get3() : " + b.get3()); // read date from b
b.set3(3); // set b.param3 to 3
console.log("b.get3() : " + b.get3()); // read date from b

// the newvar is not given with object b
console.log(b.newvar);

// add a variable to the b object
b.newvar = "new variable b";
console.log(b.newvar);

// add a function to the b object
b.newfunc = (param) => {
  return param;
}
console.log(a.newfunc("function b"));

在类的方法范围之外访问`this`

1 个答案: