Errors when response has empty relationships

[andrepcg]

In my backend I have a conversation model that olds a foreign_key to the last sent message in that conversation. If there is no last message, this normaliser fails.

Example:

import normalize from 'normalize-json-api-response';

const json = {
   "data":[
      {
         "id":"3",
         "type":"conversation",
         "attributes":{
            "created_at":"2019-09-19T10:03:44.401Z",
            "subject":"Test subject"
         },
         "relationships":{
            "last_message":{
               "data":null
            }
         }
      },
   ],
   "included":[]
};

normalize(json)

Uncaught (in promise) TypeError: Cannot read property 'constructor' of null at normalize (index.js:57) (

Normalize-JSON-API/src/index.ts

Line 51 in 7443bb3

if (relation.data.constructor === Array) {

)

I also had occasions where it would fail on line 53 (

Normalize-JSON-API/src/index.ts

Line 53 in 7443bb3

if (!relation.data[0].hasOwnProperty('type')) {

) when relation.data[0] would be undefined.

I have temporarily fixed this in the backend by not serializing fields that are empty but that's going to be cumbersome to do across all serializers.

---

Also, if the serializer does not include any relationship, and thus the included attribute does not exist, the normalizer crashes as well (

Normalize-JSON-API/src/functions/find-items.ts

Line 23 in 7443bb3

response.included.find((item: any) => (String(item.id) === String(temp.id)) &&

). Do you plan on supporting these "features"? I can fork the repo use that if it's something you don't want to support

[SinestroWhite]

The problem does not come from the empty included field. Look at your last_message in your example:
"relationships":{ "last_message":{ "data":null } }
the data field here must not be null. It has to be something of this sort
{ "type": "people", "id": "9" }

The reason it crashes on line 53 is because the data field does not have type subfield.
This is required by the JSON::API specification. If you don't have a last_massage relation, modify your API so that it doesn't respond with a null value.

Thank you very much for your contribution. I will review it and I will post a comment here at a later date.

[andrepcg]

I'm using https://github.com/Netflix/fast_jsonapi and it's not directly compatible with this lib without making some backend changes. Basically, if a model has a relationship and it's empty (by empty I mean it's null), fast_jsonapi serializes it to null.

[SinestroWhite]

Yeah, I got it and you are right that a null value must not give an error.