type fields weren't consistent - in some cases
type were used to define the model, but in some other cases they had to be defined separately. In v2, this will be consistent and it will need to be defined explicitly.
Removed deprecated stuff
Stricter action support
In v1, some of the mutations have been automatically wrapped into actions. In v2 this is only done in some cases where multiple changes are being done (e.g. the
model.update() method). This will be a breaking change if you're using the MobX strict mode
Snapshot/patch format changes
The serialised format of the model is a bit different, more specifically the meta object inside of it. This is a breaking change if you depend on the snapshot structure or you want to reuse v1 snapshots in v2 (or vice versa).
References to missing models
In v1, if a model had a reference to another model that is not in a collection, it would return the model id instead of the instance. In v2, such models will be skipped - this means that the reference value will always be either a model or an array of models.
JSON API pagination
The pagination is now using methods instead of just plain property access:
await response.next becomes
config.cache is no longer a boolean, but a
CachingStrategy enum instead.
true maps to
false maps to
JSON API Collection caching
cache property on the collection is no longer a boolean. It's a
CachingStrategy enum instead, without any default value (the global fallback is used).
Response data is
null instead of
 when no data
In v1, empty data would fall back to
 during response parsing, which is not technically correct. In v2, the response data value will be the same as the API response.
Endpoint function base URL
In v1, the return value of the endpoint function would be appended to the base url, which made some operations where a model has a different base url much harder. In v2, this is not done (it's still done when there is no endpoint or when it's a string) - instead, the endpoint function receives a baseurl parameter, and you are responsible of prepending it to your endpoint url.
JSON API IRequestOptions options changes
IRequestOptions into three parts -
JSON API saves only send dirty fields
Unlike v1 (but as the spec requres), when saving a model in v2 will do a
PATCH request with only the changed attributes and relationships. This shouldn't be an issue if the server is also implementing the spec correctly.