GraphQL ObjectType with dynamic fields based on arguments

Question

We are in the situation that the response of our GraphQL Query has to return some dynamic properties of an object. In our case we are not able to predefine all possible prop

Answer 1

One more possible solution could be to declare any such dynamic object as a string. And then pass a stringified version of the object as value to that object from your resolver functions. And then eventually you can parse that string to JSON again to make it again an object on the client side.

I'm not sure if its recommended way or not but I tried to make it work with this approach and it did work smoothly, so I'm sharing it here.

Answer 2

Neither option is really viable:

1. GraphQL is strongly typed. GraphQL.js doesn't support some kind of any field, and all types defined in your schema must have fields defined. If you look in the docs, fields is a required -- if you try to leave it out, you'll hit an error.

2. Args are used to resolve queries on a per-request basis. There's no way you can pass them back to your schema. You schema is supposed to be static.

As you suggest, it's possible to accomplish what you're trying to do by rolling your own customer Scalar. I think a simpler solution would be to just use JSON -- you can import a custom scalar for it like this one. Then just have your elements field resolve to a JSON object or array containing the dynamic fields. You could also manipulate the JSON object inside the resolver based on arguments if necessary (if you wanted to limit the fields returned to a subset as defined in the args, for example).

Word of warning: The issue with utilizing JSON, or any custom scalar that includes nested data, is that you're limiting the client's flexibility in requesting what it actually needs. It also results in less helpful errors on the client side -- I'd much rather be told that the field I requested doesn't exist or returned null when I make the request than to find out later down the line the JSON blob I got didn't include a field I expected it to.