plainToClass to call object.method() in web worker thread

Question

I am using angular, trying to pass an object to the web worker for the background process. the class is

Article{
  method1();
  propertyA;
}

addEventListener('message', ({ data }) => {
  // if without plainToClass, how to call article.method1()
  data.article=plainToClass(Article, data.article);
  console.log(data.article.method1());
});

Because in the web worker thread, I want to use article.method1(),

1. After the object is passed to web worker, it becomes an object that does not have methods but only properties. Why is this? pass as a string?

2. Tried to use plainToClass() to convert the passed obj to an Object with method, which in main thread I am able to do so, load string and convert to Class object. but in web worker, it complains about Reflect.getMetadata is not a function. Which seems it cannot find the imported import 'reflect-metadata' in polyfills.ts

Answer:

It turns out I need to import this in Article class file

import 'reflect-metadata';
export class Article implements Clonable{
}

Answer 1

Passing data to a Web worker is done by serializing the object, so you won't be able to pass in behavior. Instead, you'll need to either use plainToClass as you have in your example, or you can provide the functionality in a helper function.

Additionally, import reflect-metadata is an import for side-effects. This code is run once per context, so it will need to be run again inside the worker, and then plainToClass should work.

That said, a simpler approach might be to try to call the class constructor using the values passed in - if that’s possible?