🗒️TypeScript 5.0 装饰器

function debugMethod(_target: unknown, memberName: string, propertyDescriptor: PropertyDescriptor) {
  return {
    get() {
      const wrapperFunction = (...arguments_: unknown[]) => {
        const now = new Date(Date.now());
        console.log('start time', now.toISOString());
        propertyDescriptor.value.apply(this, arguments_);
        const end = new Date(Date.now());
        console.log('end time', end.toISOString());
      };
      Object.defineProperty(this, memberName, {
        value: wrapperFunction,
        configurable: true,
        writable: true,
      });
      return wrapperFunction;
    },
  };
}
class ComplexClass {
  @debugMethod
  public complexMethod(_a?: number): void {
    console.log("DOING STUFF!");
  }
}

{
  "compilerOptions": {
    "strict": true,
    "experimentalDecorators": true,
    "target": "ES2017",
    "jsx": "react",
    "module": "ESNext",
    "moduleResolution": "node"
  }
}

function debugMethod<This, Args extends any[], Return>(
  originalMethod: (this: This, ...args: Args) => Return, 
  context: ClassMethodDecoratorContext<This, (this: This, ...args: Args) => Return>
) {
  const methodName = String(context.name);
  function replacementMethod(this: This, ...args: Args) {
    const now = new Date(Date.now());
    console.log(`${methodName} start time`, now.toISOString());
    const result = originalMethod.call(this, ...args);
    const end = new Date(Date.now());
    console.log(`${methodName} end time`, end.toISOString());
    return result;
  }
  return replacementMethod;
}

class ComplexClass {
  @debugMethod
  complexMethod(_a?: number): void {
    console.log("DOING STUFF!");
  }
}

new ComplexClass().complexMethod()

function kkk(str:string) {
  console.log(`装饰器工厂 求值 @kkk(): ${str}`);
  return (
    value:any, context:any
  ) => console.log(`装饰器应用 @kkk(): ${str}`) 
}

function jjj(value: any, context: any) {
  return console.log(`装饰器应用 @jjj() ${context.name}`)
}

function log(str:string) {
  console.log(str);
  return str;
}

@kkk('类装饰器')
class T {
  @kkk('静态属性装饰器')
  @jjj
  static staticField = log('静态属性值');

  @kkk('原型方法')
  @jjj
  [log('计算方法名')]() {}

  @kkk('实例属性')
  instanceField = log('实例属性值');

  @kkk('静态方法装饰器')
  static fn(){}
}

[LOG]: "装饰器工厂 求值 @kkk(): 类装饰器" 
[LOG]: "装饰器工厂 求值 @kkk(): 静态属性装饰器" 
[LOG]: "装饰器工厂 求值 @kkk(): 原型方法" 
[LOG]: "计算方法名" 
[LOG]: "装饰器工厂 求值 @kkk(): 实例属性" 
[LOG]: "装饰器工厂 求值 @kkk(): 静态方法装饰器" 
[LOG]: "装饰器应用 @kkk(): 静态方法装饰器" 
[LOG]: "装饰器应用 @jjj() 计算方法名" 
[LOG]: "装饰器应用 @kkk(): 原型方法" 
[LOG]: "装饰器应用 @jjj() staticField" 
[LOG]: "装饰器应用 @kkk(): 静态属性装饰器" 
[LOG]: "装饰器应用 @kkk(): 实例属性" 
[LOG]: "装饰器应用 @kkk(): 类装饰器" 
[LOG]: "静态属性值"