An object providing the discriminator logic or a string/number
that will be stored into the _type attribute.
Optionalparent: ClazzOrModelSchema<any>When there are multiple levels of hierarchy involved you may provide this argument to indicate the main schema used for deserialization. When not give the parent schema is inferred as the direct parent (the class/schema that is extended).
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
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
Sometimes, when working with schema hierarchies, we may want to deserialize an object to a specific sub-schema. The
subSchemadecorator 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.