当作为表达式调用时无法解析类装饰器的签名

Question

我正在尝试遵循此示例。我无法编译它。关于如何解决问题的任何想法？

import { Component } from '@angular/core';

function log(className)
{
  console.log(className)

  return (...args) => {
    console.log("Arguments passed to this class's constructor are ", args)
    return new className(...args)
  }
}

@log
class myExampleClass
{
    constructor(arg1, arg2)
    {
      console.log("Constructor fired!")
    }
}

const myClass = new myExampleClass(5,10)

我得到的错误是。

Unable to resolve signature of class decorator when called as an expression.
  Type '(...args: any[]) => any' is not assignable to type 'typeof myExampleClass'.
    Type '(...args: any[]) => any' provides no match for the signature 'new (arg1: any, arg2: any): myExampleClass'.

Answer 1

类装饰器应用于类的构造函数，可用于观察、修改或替换类定义。

在您的示例中，您尝试替换类定义。在这种情况下，您必须返回您的 @log 装饰器应用到的同一类的类型。

function log<T extends { new(...args: any[]): {} }>(className: T) {
  console.log(className)
  return class extends className {
    constructor(...args) {
      super(...args);
      console.log("Arguments passed to this class's constructor are ", args)
    }
  }
} 

另见：

• https://www.typescriptlang.org/docs/handbook/decorators.html#class-decorators