从同一个类中的另一个方法调用一个方法 [英] Calling a method from another method in the same class

问题描述

为什么会出现错误:未捕获的TypeError:self.myTest不是函数"?如何在javascript类的另一个方法中调用一个方法?

Why am I getting the error: "Uncaught TypeError: self.myTest is not a function"? How do I call a method from within another method in a javascript class?

class MyClass {

    myTest() {
      console.log('it works');
    }

    runMyTest() {
      self.myTest();
    }

}

var myClass = new MyClass();
myClass.runMyTest();

推荐答案

您需要使用this关键字而不是self.

You need to use the this keyword instead of self.

runMyTest() {
    this.myTest();
}

旁注

如果要嵌套标准函数符号，则this不受词法约束(将是未定义的).要解决此问题，请使用箭头功能(首选)，.bind，或在功能外部局部定义this.

If you are nesting standard functions notation then this is not lexically bound (will be undefined). To get around this, use Arrow Functions (preferred), .bind, or locally define this outside of the function.

class Test {
  constructor() {
    this.number = 3;
  }

  test() {
    function getFirstThis() {
       return this;
    }

    const getSecondThis = () => {
       return this;
    };

    const getThirdThis = getFirstThis.bind(this);
    
    const $this = this;
    function getFourthThis() {
      return $this;
    }

    // undefined
    console.log(getFirstThis());
    
    // All return "this" context, containing the number property
    console.log(this); 
    console.log(getSecondThis());
    console.log(getThirdThis());
    console.log(getFourthThis());
  }
}

new Test().test();

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