typescript_decorator.ts

@classDecFactory()
class Student {
  @propertyDecFactory()
  name: string

  @methodDecFactory()
  run(@parameterDecFactory() arg: string) {
    console.log(arg)
  }
}

function classDecFactory(): ClassDecorator {
  return (target) => {
    console.log('classDecFactory', target, typeof target)
  }
}

function propertyDecFactory(): PropertyDecorator {
  return (target, propertyKey) => {
    console.log('propertyDecFactory', target, typeof target)
  }
}

function methodDecFactory(): MethodDecorator {
  return (target, propertyKey, descriptor) => {
    console.log('methodDecFactory', target, typeof target)
  }
}

function parameterDecFactory(): ParameterDecorator {
  return (target, propertyKey, parameterIndex) => {
    console.log('parameterDecFactory', target, typeof target)
  }
}