Collections

Use collection() to serialize many resources with the same Resource class.

const payload = UserResource.collection(users);

Output:

{
  "data": [
    {
      "id": 1,
      "name": "John"
    },
    {
      "id": 2,
      "name": "Jane"
    }
  ]
}

Collection items are validated with the static schema when one exists. If a validation error occurs, the thrown ResourceValidationError includes the failing itemIndex.

try {
  UserResource.collection(users);
} catch (error) {
  if (error instanceof ResourceValidationError) {
    console.log(error.resourceName);
    console.log(error.itemIndex);
  }
}

Nested Collections

Collections can be nested inside another Resource. The outer Resource receives the collection’s data array, not another envelope.

class UserResource extends Resource<User> {
  toArray() {
    return {
      id: this.resource.id,
      posts: PostResource.collection(this.resource.posts),
    };
  }
}