support custom scalar type when using fast-json-stringify serializer

package.json

@@ -82,6 +82,7 @@
     "eslint": "^8.49.0",
     "eslint-config-prettier": "^9.0.0",
     "graphql": "^16.8.0",
+    "graphql-scalars": "^1.22.4",
     "jest": "^29.7.0",
     "lint-staged": "^14.0.1",
     "prettier": "^3.0.3",

src/__tests__/__snapshots__/json.test.ts.snap

@@ -66,6 +66,15 @@ exports[`json schema creator json schema creation 1`] = `
             "author": {
               "nullable": false,
               "properties": {
+                "email": {
+                  "nullable": true,
+                  "type": "string",
+                },
+                "extra": {
+                  "additionalProperties": true,
+                  "nullable": true,
+                  "type": "object",
+                },
                 "id": {
                   "nullable": false,
                   "type": "string",

src/__tests__/json.test.ts

@@ -10,8 +10,10 @@ import {
   GraphQLString,
   parse,
   GraphQLInt,
-  versionInfo
+  versionInfo,
+  GraphQLScalarType
 } from "graphql";
+import { GraphQLEmailAddress, GraphQLJSONObject } from "graphql-scalars";
 import { buildExecutionContext } from "graphql/execution/execute";
 import { compileQuery } from "../index";
 import { queryToJSONSchema } from "../json";
@@ -36,6 +38,12 @@ describe("json schema creator", () => {
       },
       recentArticle: {
         type: BlogArticle
+      },
+      email: {
+        type: GraphQLEmailAddress
+      },
+      extra: {
+        type: GraphQLJSONObject
       }
     })
   });
@@ -83,7 +91,11 @@ describe("json schema creator", () => {
       isPublished: true,
       author: {
         id: 123,
-        name: "John Smith"
+        name: "John Smith",
+        email: "[email protected]",
+        extra: {
+          foo: "bar"
+        }
       },
       title: "My Article " + id,
       body: "This is a post",
@@ -106,6 +118,8 @@ describe("json schema creator", () => {
         author {
           id
           name
+          email
+          extra
           pic(width: 640, height: 480) {
             url
             width
@@ -137,7 +151,10 @@ describe("json schema creator", () => {
         })
       : (buildExecutionContext as any)(blogSchema, document);
   context.options = {};
-  const jsonSchema = queryToJSONSchema(context);
+  const jsonSchema = queryToJSONSchema(context, {
+    EmailAddress: "string",
+    JSONObject: "object"
+  });
   test("json schema creation", () => {
     expect(jsonSchema).toMatchSnapshot();
   });
@@ -148,7 +165,11 @@ describe("json schema creator", () => {
     });
     test("valid response serialization", async () => {
       const prepared: any = compileQuery(blogSchema, document, "", {
-        customJSONSerializer: true
+        customJSONSerializer: true,
+        customJSONSerializerScalarTypes: {
+          EmailAddress: "string",
+          JSONObject: "object"
+        }
       });
       const response = await prepared.query(undefined, undefined, {});
       expect(prepared.stringify).not.toBe(JSON.stringify);

src/execution.ts

@@ -51,7 +51,7 @@ import {
 } from "./ast";
 import { GraphQLError as GraphqlJitError } from "./error";
 import createInspect from "./inspect";
-import { queryToJSONSchema } from "./json";
+import { CustomScalarTypes, queryToJSONSchema } from "./json";
 import { createNullTrimmer, NullTrimmer } from "./non-null";
 import {
   createResolveInfoThunk,
@@ -70,6 +70,9 @@ const inspect = createInspect();
 export interface CompilerOptions {
   customJSONSerializer: boolean;
 
+  // To support serializing custom scalar type using fast-json-stringify
+  customJSONSerializerScalarTypes?: CustomScalarTypes;
+
   // Disable builtin scalars and enum serialization
   // which is responsible for coercion,
   // only safe for use if the output is completely correct.
@@ -254,7 +257,10 @@ export function compileQuery<
 
     let stringify: (v: any) => string;
     if (options.customJSONSerializer) {
-      const jsonSchema = queryToJSONSchema(context);
+      const jsonSchema = queryToJSONSchema(
+        context,
+        options.customJSONSerializerScalarTypes
+      );
       stringify = fastJson(jsonSchema);
     } else {
       stringify = JSON.stringify;

src/json.ts

@@ -40,14 +40,24 @@ const PRIMITIVES: {
   ID: "string"
 };
 
+export type CustomScalarTypes = {
+  [key: string]:
+    | IntegerSchema["type"]
+    | NumberSchema["type"]
+    | StringSchema["type"]
+    | BooleanSchema["type"]
+    | ObjectSchema["type"];
+};
+
 /**
  * GQL -> JSON Schema transform
  *
  * @param compilationContext
  * @return     {object}  A plain JavaScript object which conforms to JSON Schema
  */
 export function queryToJSONSchema(
-  compilationContext: CompilationContext
+  compilationContext: CompilationContext,
+  customScalarTypes?: CustomScalarTypes
 ): Schema {
   const type = getOperationRootType(
     compilationContext.schema,
@@ -75,7 +85,8 @@ export function queryToJSONSchema(
     fieldProperties[responseName] = transformNode(
       compilationContext,
       fields[responseName],
-      fieldType.type
+      fieldType.type,
+      customScalarTypes
     );
   }
   return {
@@ -125,7 +136,8 @@ export function queryToJSONSchema(
 function transformNode(
   compilationContext: CompilationContext,
   fieldNodes: FieldNode[],
-  type: GraphQLType
+  type: GraphQLType,
+  customScalarTypes?: CustomScalarTypes
 ): Exclude<Schema, RefSchema> {
   if (isObjectType(type)) {
     const subfields = collectSubfields(compilationContext, type, fieldNodes);
@@ -144,7 +156,8 @@ function transformNode(
       properties[responseName] = transformNode(
         compilationContext,
         subfields[responseName],
-        fieldType.type
+        fieldType.type,
+        customScalarTypes
       );
     }
     return {
@@ -156,12 +169,22 @@ function transformNode(
   if (isListType(type)) {
     return {
       type: "array",
-      items: transformNode(compilationContext, fieldNodes, type.ofType),
+      items: transformNode(
+        compilationContext,
+        fieldNodes,
+        type.ofType,
+        customScalarTypes
+      ),
       nullable: true
     };
   }
   if (isNonNullType(type)) {
-    const nullable = transformNode(compilationContext, fieldNodes, type.ofType);
+    const nullable = transformNode(
+      compilationContext,
+      fieldNodes,
+      type.ofType,
+      customScalarTypes
+    );
     nullable.nullable = false;
     return nullable;
   }
@@ -172,19 +195,31 @@ function transformNode(
     };
   }
   if (isScalarType(type)) {
-    const jsonSchemaType = PRIMITIVES[type.name];
+    const jsonSchemaType =
+      PRIMITIVES[type.name] ?? customScalarTypes?.[type.name];
     if (!jsonSchemaType) {
       throw new Error(`Got unexpected PRIMITIVES type: ${type.name}`);
     }
+
+    const additionalProperties =
+      jsonSchemaType.toString() === "object"
+        ? { additionalProperties: true }
+        : undefined;
     return {
       type: jsonSchemaType,
-      nullable: true
+      nullable: true,
+      ...additionalProperties
     };
   }
   if (isAbstractType(type)) {
     return compilationContext.schema.getPossibleTypes(type).reduce(
       (res, t) => {
-        const jsonSchema = transformNode(compilationContext, fieldNodes, t);
+        const jsonSchema = transformNode(
+          compilationContext,
+          fieldNodes,
+          t,
+          customScalarTypes
+        );
         (res as ObjectSchema).properties = {
           ...(res as ObjectSchema).properties,
           ...(jsonSchema as ObjectSchema).properties

yarn.lock

@@ -2843,6 +2843,13 @@ graphemer@^1.4.0:
   resolved "https://registry.yarnpkg.com/graphemer/-/graphemer-1.4.0.tgz#fb2f1d55e0e3a1849aeffc90c4fa0dd53a0e66c6"
   integrity sha512-EtKwoO6kxCL9WO5xipiHTZlSzBm7WLT627TqC/uVRd0HKmq8NXyebnNYxDoBi7wt8eTWrUrKXCOVaFq9x1kgag==
 
+graphql-scalars@^1.22.4:
+  version "1.22.4"
+  resolved "https://registry.yarnpkg.com/graphql-scalars/-/graphql-scalars-1.22.4.tgz#af092b142bcfd5c1f8c53cb70ee1955ecd4ddb03"
+  integrity sha512-ILnv7jq5VKHLUyoaTFX7lgYrjCd6vTee9i8/B+D4zJKJT5TguOl0KkpPEbXHjmeor8AZYrVsrYUHdqRBMX1pjA==
+  dependencies:
+    tslib "^2.5.0"
+
 graphql@^16.8.0:
   version "16.8.1"
   resolved "https://registry.yarnpkg.com/graphql/-/graphql-16.8.1.tgz#1930a965bef1170603702acdb68aedd3f3cf6f07"