Function subSchema

Sometimes, when working with schema hierarchies, we may want to deserialize an object to a specific sub-schema. The subSchema decorator is used to handle such scenario. What schema is picked among those available is decided using a "discriminator". The discriminator can be a string (which is added to the serialized object) or a object containing callbacks allowing for more complex behaviour.

Example

  class Todo {
     @serializable
      id: string;

      @serializable
      text: string;
  }

  @subSchema("picture")
  class PictureTodo extends Todo {
      @serializable
      pictureUrl: string;
  }

  const ser = serialize(Object.assign(new PictureTodo(), {
      id: "pic1",
      text: "Lorem Ipsum",
      pictureUrl:"foobar",
  }));
  // ser now holds an object like the following result
  // {
  //    id: "pic1",
  //    _type: "picture"
  //    text: "Lorem Ipsum",
  //    pictureUrl:"foobar",
  // }
  const deser = deserialize(Todo, ser);
  console.log(deser instanceof PictureTodo); // true

Example

Using the parent argument it's possible to specify the subschema parent instead of relying on auto-detention.

  class Todo {
     @serializable
      id: string;

      @serializable
      text: string;
  }

  @subSchema("picture")
  class PictureTodo extends Todo {
      @serializable
      pictureUrl: string;
  }

  @subSchema("betterPicture", Todo)
  class BetterPictureTodo extends PictureTodo {
      @serializable
      altText: string;
  }


  const ser = serialize(Object.assign(new BetterPictureTodo(), {
      id: "pic1",
      text: "Lorem Ipsum",
      pictureUrl:"foobar",
      altText: "Alt text",
  }));
  // ser now holds an object like the following result
  // {
  //    id: "pic1",
  //    _type: "betterPicture"
  //    text: "Lorem Ipsum",
  //    pictureUrl:"foobar",
  //    altText: "Alt text",
  // }
  const deser = deserialize(Todo, ser);
  console.log(deser instanceof BetterPictureTodo); // true
  console.log(deser instanceof PictureTodo); // true

  const ser2 = serialize(Object.assign(new PictureTodo(), {
      id: "pic2",
      text: "Lorem Ipsum",
      pictureUrl:"foobar",
  }));
  // ser2 now holds an object like the following result
  // {
  //    id: "pic2",
  //    _type: "picture"
  //    text: "Lorem Ipsum",
  //    pictureUrl:"foobar",
  // }
  const deser2 = deserialize(Todo, ser2);
  console.log(deser2 instanceof BetterPictureTodo); // false
  console.log(deser2 instanceof PictureTodo); // true

Returns