dataIdFromObject overwriting cache from other queries incorrectly

Question

So using dataIdFromObject as the following:

cache: new InMemoryCache({
      dataIdFromObject: object => {
        switch (object.__typename) {
          case 'AppKey':
            return object.appKeyId
          case 'App':
            return object.appId
          default:
            return defaultDataIdFromObject(object)
        }
      },
    })

is some how rewriting the first object.name in appKey from app, or sometimes vice versa. For example

data.getAppKeys = [{ appKeyId: 1, name: 'My App' }, ...correctObjects] when the backend has the key as {appKeyId: 1, name: 'myAppKey'}. This doesn't occur when commenting out either of the cases from dataIdFromObject.

How can I get the cache to rewrite the correct queries?

Answer 1

You need to have a unique identifier that goes beyond a number, because the numbers will match and the cache will overwrite incorrectly, the solution was is add the __typename into the data identifier like so:

dataIdFromObject: object => {
        const getID = (typename, id) => `${typename}_${id}`

        switch (object.__typename) {
          case 'AppKey':
            return getID(object.__typename, object.appKeyId)
          case 'App':
            return getID(object.__typename, object.appId)
          default:
            return getId(object.__typename, defaultDataIdFromObject(object))
        }
      },
    })