feat(codegen): expose referenced type as hidden symbol

packages/@sanity/codegen/src/typescript/typeGenerator.ts

@@ -11,6 +11,8 @@ import {
   type UnionTypeNode,
 } from 'groq-js'
 
+const REFERENCE_SYMBOL_NAME = 'internalGroqTypeReferenceTo'
+
 /**
  * A class used to generate TypeScript types from a given schema
  * @internal
@@ -71,6 +73,18 @@ export class TypeGenerator {
     return new CodeGenerator(t.exportNamedDeclaration(typeAlias)).generate().code
   }
 
+  static generateKnownTypes(): string {
+    const typeOperator = t.tsTypeOperator(t.tsSymbolKeyword())
+    typeOperator.operator = 'unique'
+
+    const identifier = t.identifier(REFERENCE_SYMBOL_NAME)
+    identifier.typeAnnotation = t.tsTypeAnnotation(typeOperator)
+
+    const decleration = t.variableDeclaration('const', [t.variableDeclarator(identifier)])
+    decleration.declare = true
+    return new CodeGenerator(t.exportNamedDeclaration(decleration)).generate().code
+  }
+
   /**
    * Since we are sanitizing identifiers we migt end up with collisions. Ie there might be a type mux.video and muxVideo, both these
    * types would be sanityized into MuxVideo. To avoid this we keep track of the generated type names and add a index to the name.
@@ -204,6 +218,15 @@ export class TypeGenerator {
         }
       }
     }
+    if (typeNode.dereferencesTo !== undefined) {
+      const derefType = t.tsPropertySignature(
+        t.identifier(REFERENCE_SYMBOL_NAME),
+        t.tsTypeAnnotation(t.tsLiteralType(t.stringLiteral(typeNode.dereferencesTo))),
+      )
+      derefType.computed = true
+      derefType.optional = true
+      props.push(derefType)
+    }
     return t.tsTypeLiteral(props)
   }
 

packages/sanity/src/_internal/cli/threads/codegenGenerateTypes.ts

@@ -58,7 +58,10 @@ async function main() {
   const schema = await readSchema(opts.schemaPath)
 
   const typeGenerator = new TypeGenerator(schema)
-  const schemaTypes = typeGenerator.generateSchemaTypes()
+  const schemaTypes = [
+    typeGenerator.generateSchemaTypes(),
+    TypeGenerator.generateKnownTypes(),
+  ].join('\n')
   const resolver = getResolver()
 
   parentPort?.postMessage({