如何获得对 JavaScript 中的 class 方法的静态引用？

Question

假设我想传递对 JavaScript 中 class 方法的引用：

class Example {
  constructor() {
    this.field = "value"
  }
  exampleMethod() {
    console.log(this.field)
  }
  exampleMethod2() {
    this.field += "."
  }
}

// get references to the methods without having an instance of the object (important detail)
let methods = [Example.exampleMethod, Example.exampleMethod2]  // not correct
let sampledMethod = methods[Math.floor(Math.random()*methods.length)]
let object = new Example()
object.sampledMethod()

奇怪的例子，但是说我有更合理的理由想要这些没有对象实例的引用。有干净的方法吗？

Answer 1

方法存在于对象的原型上。要在对象实例上调用分离方法，请使用 .call or .apply:

class Example {
  constructor() {
    this.field = "value"
  }
  exampleMethod() {
    console.log(this.field)
  }
  exampleMethod2() {
    this.field += "."
  }
}

let methods = [Example.prototype.exampleMethod, Example.prototype.exampleMethod2];
let sampledMethod = methods[Math.floor(Math.random() * methods.length)];

let object = new Example();
console.log(object);
console.log('Calling', sampledMethod);
sampledMethod.call(object);
console.log(object);

如何获得对 JavaScript 中的 class 方法的静态引用？

How do you get a static reference to a method of a class in JavaScript?

javascript

methods

static