如何在javascript中实例化另一个类中的类？

Question

如何在javascript中实例化另一个类中的类？类有静态方法和非静态方法

export default class MyClass {
    static staticMethod() {
        return console.log(`this is static method`);
    }

    nonStaticMethod() {
        return console.log(`this is not static method`);
    }

}

我可以从上面访问一些其他js文件中的静态方法，它是这样的类：

import MyClass form "somewhere";
MyClass.staticMethod(); //this works 

但是如何访问非静态方法呢？

//This does not work
import MyClass form "somewhere";
MyClass.nonStaticMethod();

为了使其正常工作，需要创建/传递MyClass的实例。我怎么能做这样的事情呢？

let myClass = new MyClass();
myClass.nonStaticMethod();
//I am getting uncaught ReferenceError: nonStaticMethod is not defined

Answer 1

创建类的一个实例，然后调用该实例方法。你不能在这样的静态上下文中调用实例方法。参见下面的示例代码：

​

class ClassA {
  static staticMethod() {
    return 'this is static method';
  }

  nonStaticMethod() {
    return 'this is not static method';
  }
}

//Call static method:
console.log(ClassA.staticMethod()); //Works as expected
//ClassA.nonStaticMethod(); // Uncomment and see it Will cause a Uncaught TypeError

//Call instance method:
const instance = new ClassA();
//console.log(instance.staticMethod());  // Uncomment and see it Will cause a Uncaught TypeError
console.log(instance.nonStaticMethod()); //Works as expected

​

Answer 2

我真的看不出有什么问题。这段代码运行得很好。

​

class myClass {
    static staticMethod() {
        return console.log(`this is static method`);
    }

    nonStaticMethod() {
        return console.log(`this is not static method`);
    }
}

myClass.staticMethod();
let classInstance = new myClass();
classInstance.nonStaticMethod();

​