feat(codegen): expose referenced type as hidden symbol (#6008)

Author: sgulseth

packages/@sanity/codegen/src/typescript/__tests__/__snapshots__/typeGenerator.test.ts.snap

@@ -1,5 +1,7 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`generateSchemaTypes can generate well known types 1`] = `"export declare const internalGroqTypeReferenceTo: unique symbol;"`;
+
 exports[`generateSchemaTypes generateTypeNodeTypes should be able to generate types for type nodes: boolean 1`] = `"export type test_2 = boolean;"`;
 
 exports[`generateSchemaTypes generateTypeNodeTypes should be able to generate types for type nodes: null 1`] = `"export type test_5 = null;"`;
@@ -30,9 +32,11 @@ export type Post = {
   author?: {
     _ref: string;
     _weak?: boolean;
+    [internalGroqTypeReferenceTo]?: \\"author\\";
   } | {
     _ref: string;
     _weak?: boolean;
+    [internalGroqTypeReferenceTo]?: \\"ghost\\";
   };
   slug?: Slug;
   excerpt?: string;
@@ -41,6 +45,7 @@ export type Post = {
     asset: {
       _ref: string;
       _weak?: boolean;
+      [internalGroqTypeReferenceTo]?: \\"sanity.imageAsset\\";
     };
     caption?: string;
     attribution?: string;

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

@@ -24,6 +24,12 @@ describe('generateSchemaTypes', () => {
     expect(typeDeclarations).toMatchSnapshot()
   })
 
+  test('can generate well known types', async () => {
+    const typeDeclarations = TypeGenerator.generateKnownTypes()
+
+    expect(typeDeclarations).toMatchSnapshot()
+  })
+
   test('should generate correct types for document schema with string fields', () => {
     const schema: SchemaType = [
       {
@@ -247,6 +253,7 @@ describe('generateSchemaTypes', () => {
     _ref: string;
     _type: \\"reference\\";
     _weak?: boolean;
+    [internalGroqTypeReferenceTo]?: \\"author\\";
   };
 };
 

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({