javascript - 控制台日志不从构造函数打印

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javascript中存在三个具有继承性的类。当我删除中间类中的 super() 时，子构造函数不再打印 console.log。但是当我将 super() 放在中类中时，所有 3 个控制台日志都会显示。想知道为什么缺少中间的 super() 甚至取消了子控制台日志。

class Great {
    constructor() {
        console.log('this is great');
    }
}

class Grand extends Great {
    constructor() {
        // super();
        console.log('this is grand');
    }
}

class Father extends Grand {
    constructor() {
        super();
        console.log('I am your father');
    }
}

function main() {
    let dad = new Father();
}

main();

我希望控制台显示“这太棒了”和“我是你的父亲”。但在评论中间类的 super 时，唯一出现的就是“这太伟大了”。

Answer 1

class Great {
  constructor() {
    console.log('this is great');
  }
}

class Grand extends Great {
  constructor() {
    // super();
    console.log('this is grand');
  }
}

class Father extends Grand {
  constructor() {
    // calls Grand constructor function and its console.log
    super();
    // ReferenceError: must call super constructor before using 'this' in derived class constructor
    // The Grand constructor throws an error preventing the next line to be executed
    console.log('I am your father');
  }
}

function main() {
  let dad = new Father();
}

main();

与以下内容相同:

const functionWithError = () => {
  console.log('I am about to throw');
  throw new Error('Throwing...');
}

const functionThatCallsFunctionWithError = () => {
  functionWithError();
  console.log('This console.log will never be called');
}

functionThatCallsFunctionWithError();