graphql-js error encountered in the `/learn` pages

[jfcisco]

Description

Instead of showing the result of the GraphQL query in the web page, the output box shows an error.

Steps to Reproduce

1. Open a browser and navigate to either of the following:
   • https://graphql.org/learn/queries/#fields
   • https://graphql.org/learn/schema/#union-types

Expected Result

The field name returns a String type, in this case the name of the main hero of Star Wars, "R2-D2".

Actual Result

data property is null and an error is shown in the output box. For example, the /learn/queries/#fields section shows this error:

{
  "errors": [
    {
      "message": "Support for returning GraphQLObjectType from resolveType was removed in graphql-js@16.0.0 please return type name instead.",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ],
      "path": [
        "hero"
      ]
    }
  ],
  "data": {
    "hero": null
  }
}

Additional Context

I was able to reproduce the issue on Chrome 107.0.5304.107 and Firefox Developer Edition 107.0b9 (64-bit)

[jfcisco]

I think the code that needs to change is this part:

graphql.github.io/src/components/Marked/swapiSchema.tsx

Lines 383 to 393 in 48a374a

	Character: {
	__resolveType(data, context, info){
	if(humanData[data.id]){
	return info.schema.getType('Human');
	}
	if(droidData[data.id]){
	return info.schema.getType('Droid');
	}
	return null;
	},
	},

Like, the line return info.schema.getType('Human'); should be return 'Human'; instead

Similar changes are needed for lines 467 to 480

[XtofX]

this looks to be the change that introduced the issue:
https://github.com/graphql/graphql.github.io/pull/1293/files

[isConic]

Getting the same error when visiting https://graphql.org/learn/queries/

---

I chose the wrong day to learn graphql 😂

[Urigo]

That was my bad!
Rushed to update graphql-js to latest....

Thanks everyone for reporting
Solved thanks to @patrick91 in #1312