PathBuilder args merge of old & new values

[samueldepooter]

Hi,

I was using the apollo-link-rest pathBuilder to map props to the request options. But I noticed that the pathBuilder function receives args

pathBuilder?: (args: object) => string;

that consist of a merge of old and new variables. So if I make an initial request with param1

const options = {
    variables: {
      param1,
      pathBuilder: args => ...,
    },
  };

and later make another request with only param2, the second request will consist of param1 and param2 unless I nullify param1

const options = {
    variables: {
      param2,
      pathBuilder: args => /* args now contains values of both param1 & param2? */,
    },
  };

Current behaviour
PathBuilder args consist of both old & new variable values

Expected behaviour
It would make more sense to me if the pathBuilder would only use the params stated in the variables object.

---

This has the same behaviour as seen when using fetchMore. For fetchMore it makes sense since your next request is based on the first request, but in this case it's a request that is not tied to the previous one.

It would also be nice to have some updated documentation around this feature since I cannot find it anywhere but in the source code!

[fbartho]

@samueldepooter That's a good catch! I'd love to have PRs to help fix this. I have no idea where this bug is coming from.

Additionally, you're right, we need to improve the docs. -- If you add to the docs under ./docs/ then we can submit that as a PR to apollo-link!

[fbartho]

I'd like to get this fixed in v0.3.0 @samueldepooter -- do you think you can help make a PR to fix this?

[fbartho]

I think I accidentally closed this!

[fbartho]

Heya, I just added a unit test that appears to disprove this case (227538e) , maybe there's something else going on @samueldepooter? Please let me know what you think, and I can reopen the issue.

[tomevans18]

Hi @fbartho,
Had a look through your test to confirm we are implementing this correctly.
We are experiencing a different result to your test and I think this is due to using fetchMore with updateQuery.

fetchMore({
    variables: {
        offset: data.feed.length,
        pathBuilder: pathBuilderFunction,
    },
    updateQuery: (prev, { fetchMoreResult }) => {
        if (!fetchMoreResult) return prev;
        return Object.assign({}, prev, {
            feed: [...prev.feed, ...fetchMoreResult.feed]
        });
    }
})

On running this we can see the variables are being passed correctly but the pathBuilderFunction has the original variables as the function args.

Any help around this would be much appreciated.

[fbartho]

Hey @tomevans18 I have no experience working with fetchMore and updateQuery -- if you can provide unit tests that demonstrate the problem, it would be really helpful!

I'm going on vacation in a week, and in crunch until then, so I wouldn't expect any movement from my side until mid August.

[tomevans18]

@fbartho thanks for the quick reply.
I will try to write a test case over the weekend to show the issue.