Implement custom JS resolvers in GraphQL

[michaelcompton]

@arijit

@michaelcompton

In my app, I don’t really want the auto generated addPost, because I want to add the datePublished by injecting the current time, and I don’t want the mutation to add a post to have the user in it because I’m going to add that from the JWT, so really, I want to do this

This can be easily done with pre hooks for addPost , Since we are already passing the request and JWT to the Hooks we should be able to modify the request to achieve this.

The point is that the interface changes. The user doesn’t want to use addPost because the interface for that contains fields for datePublished and author etc, so they want to use a mutation with a more appropriate interface like newPost(title: String, text: String): Post, but in the end they do want to add a post inside the implementation of that.

Same thing holds for update. I could have updatePost with a pre-hook that splits into x number of cases for the things you can do … if you are updating the text, then this must be true … if you are adding a like to the post, then this must be true, etc. But that’s naf. You’ much rather just have a mutation updatePostText(id: ID, newText: String) and likePost(id: ID).

Take, for example, a real GraphQL API like GitHub. It doesn’t contain just one mutation updateIssue. It has closeIssue, addComment, addTag, etc. The custom JS hooks is a nice way for us to allow extending your schema in that sort of direction.