Extending an Object Type in Code

[ldiego08]

(Posting here since haven't been able to get an answer from any other of channels. 😅)

So, using SDL you can add fields to an existing type like:

extend type Query {
   extraField: Int!
}

But how can I do this in code using the built-in classes (GraphQLObjectType, etc)?

Sounds like extendSchema might offer a way, but it is undocumented and I'm not sure how to use it in this case.

Is this supported?

My apologies in advance if I'm missing something really obvious.

[IvanGoncharov]

Is this supported?

@ldiego08 Yes, it's supported. Our documentation lagging behind since it had last major updated in 2016. Discussed in #1368

For example on how to use extendSchema please see our tests:
https://github.com/graphql/graphql-js/blob/master/src/utilities/__tests__/extendSchema-test.js

[CoericK]

@IvanGoncharov Sorry to ask this after a while, but do we have now docs about this?

[sibelius]

can we reopen this?

as extendSchema only works with SDL and not with graphql-js types?

[tot-ra]

+1, wanna reference external type for apollo federation as a plain string, but don't see other way than low-level string replace atm

[danielblignaut]

+1, any ideas on how to do this via code

[ostap1010]

+1, how to use "extend" with GraphQLObjectType?

[sjerratsch]

I was just experimenting with this and it turns out you can force the "extend type ..." in the SDL string output, if you do the following:

new GraphQLObjectType({
    ...
    name: "*NAME HERE*",
    astNode: {kind: "ObjectTypeExtension", name: {kind: "Name", value: "*NAME HERE*"}},
    extensionASTNodes: [{kind: "ObjectTypeExtension", name: {kind: "Name", value: "*NAME HERE*"}}],
    ...
})

You need to set both. This won't interfere with the fields, but you may need to put directives yourself in "astNode" then, not sure.

[isaacgr]

+1, how to use "extend" with GraphQLObjectType?

Is there anything like this?