Add support for setting default nullability for fields and return types

CHANGELOG.md

@@ -4,6 +4,7 @@
 <!-- here goes all the unreleased changes descriptions -->
 ### Features
 - add postinstall script for printing info on console about supporting the project
+- add support for setting default nullability for fields and return types (#297)
 
 ## v0.17.1
 ### Features

docs/types-and-fields.md

@@ -54,9 +54,11 @@ For simple types (like `string` or `boolean`) this is all that's needed but due
 
 Why use function syntax and not a simple `{ type: Rate }` config object? Because, by using function syntax we solve the problem of circular dependencies (e.g. Post <--> User), so it was adopted as a convention. You can use the shorthand syntax `@Field(() => Rate)` if you want to save some keystrokes but it might be less readable for others.
 
-For nullable properties like `averageRating` which might not be defined when a recipe has no ratings yet, we mark the class property as optional with a `?:` operator and also have to pass the `{ nullable: true }` decorator parameter. We should be aware that when we declare our type as a nullable union (e.g. `string | null`), we need to explicitly provide the type to the `@Field` decorator.
+By default, all fields are non nullable, just like properties in TypeScript. However, you can change that behavior by providing `nullableByDefault: true` option in `buildSchema` settings, described in [bootstrap guide](./bootstrap.md).
 
-In the case of lists, we may also need to define their nullability in a more detailed form. The basic `{ nullable: true | false }` setting only applies to the whole list (`[Item!]` or `[Item!]!`), so if we need a sparse array, we can control the list items' nullability via `nullable: items` (for `[Item]!`) or `nullable: itemsAndList` (for the `[Item]`) option.
+So for nullable properties like `averageRating` which might not be defined when a recipe has no ratings yet, we mark the class property as optional with a `?:` operator and also have to pass the `{ nullable: true }` decorator parameter. We should be aware that when we declare our type as a nullable union (e.g. `string | null`), we need to explicitly provide the type to the `@Field` decorator.
+
+In the case of lists, we may also need to define their nullability in a more detailed form. The basic `{ nullable: true | false }` setting only applies to the whole list (`[Item!]` or `[Item!]!`), so if we need a sparse array, we can control the list items' nullability via `nullable: items` (for `[Item]!`) or `nullable: itemsAndList` (for the `[Item]`) option. Be aware that setting `nullableByDefault: true` option will also apply to lists, so it will produce `[Item]` type, just like with `nullable: itemsAndList`.
 
 In the config object we can also provide the `description` and `deprecationReason` properties for GraphQL schema purposes.
 

src/helpers/types.ts

@@ -40,7 +40,8 @@ export function convertTypeIfScalar(type: any): GraphQLScalarType | undefined {
 export function wrapWithTypeOptions<T extends GraphQLType>(
   typeOwnerName: string,
   type: T,
-  typeOptions: TypeOptions = {},
+  typeOptions: TypeOptions,
+  nullableByDefault: boolean,
 ): T {
   if (
     !typeOptions.array &&
@@ -61,15 +62,21 @@ export function wrapWithTypeOptions<T extends GraphQLType>(
 
   let gqlType: GraphQLType = type;
   if (typeOptions.array) {
-    if (typeOptions.nullable === "items" || typeOptions.nullable === "itemsAndList") {
+    if (
+      typeOptions.nullable === "items" ||
+      typeOptions.nullable === "itemsAndList" ||
+      (typeOptions.nullable === undefined && nullableByDefault === true)
+    ) {
       gqlType = new GraphQLList(gqlType);
     } else {
       gqlType = new GraphQLList(new GraphQLNonNull(gqlType));
     }
   }
   if (
     typeOptions.defaultValue === undefined &&
-    (!typeOptions.nullable || typeOptions.nullable === "items")
+    (typeOptions.nullable === false ||
+      (typeOptions.nullable === undefined && nullableByDefault === false) ||
+      typeOptions.nullable === "items")
   ) {
     gqlType = new GraphQLNonNull(gqlType);
   }

src/schema/build-context.ts

@@ -26,6 +26,10 @@ export interface BuildContextOptions {
   pubSub?: PubSubEngine | PubSubOptions;
   globalMiddlewares?: Array<Middleware<any>>;
   container?: ContainerType | ContainerGetter<any>;
+  /**
+   * Default value for type decorators, like `@Field({ nullable: true })`
+   */
+  nullableByDefault?: boolean;
 }
 
 export abstract class BuildContext {
@@ -37,6 +41,7 @@ export abstract class BuildContext {
   static pubSub: PubSubEngine;
   static globalMiddlewares: Array<Middleware<any>>;
   static container: IOCContainer;
+  static nullableByDefault: boolean;
 
   /**
    * Set static fields with current building context data
@@ -75,6 +80,10 @@ export abstract class BuildContext {
     }
 
     this.container = new IOCContainer(options.container);
+
+    if (options.nullableByDefault !== undefined) {
+      this.nullableByDefault = options.nullableByDefault;
+    }
   }
 
   /**
@@ -89,6 +98,7 @@ export abstract class BuildContext {
     this.pubSub = new PubSub();
     this.globalMiddlewares = [];
     this.container = new IOCContainer();
+    this.nullableByDefault = false;
   }
 }
 

src/schema/schema-generator.ts

@@ -543,7 +543,8 @@ export abstract class SchemaGenerator {
       throw new Error(`Cannot determine GraphQL output type for ${typeOwnerName}`!);
     }
 
-    return wrapWithTypeOptions(typeOwnerName, gqlType, typeOptions);
+    const { nullableByDefault } = BuildContext;
+    return wrapWithTypeOptions(typeOwnerName, gqlType, typeOptions, nullableByDefault);
   }
 
   private static getGraphQLInputType(
@@ -569,6 +570,7 @@ export abstract class SchemaGenerator {
       throw new Error(`Cannot determine GraphQL input type for ${typeOwnerName}`!);
     }
 
-    return wrapWithTypeOptions(typeOwnerName, gqlType, typeOptions);
+    const { nullableByDefault } = BuildContext;
+    return wrapWithTypeOptions(typeOwnerName, gqlType, typeOptions, nullableByDefault);
   }
 }

tests/functional/default-nullable.ts

@@ -0,0 +1,179 @@
+import "reflect-metadata";
+import {
+  IntrospectionSchema,
+  IntrospectionObjectType,
+  IntrospectionNonNullTypeRef,
+  IntrospectionNamedTypeRef,
+  TypeKind,
+  IntrospectionListTypeRef,
+} from "graphql";
+
+import { Field, ObjectType, Resolver, Query } from "../../src";
+import { getMetadataStorage } from "../../src/metadata/getMetadataStorage";
+import { getSchemaInfo } from "../helpers/getSchemaInfo";
+
+describe("buildSchema -> nullableByDefault", () => {
+  let SampleObjectClass: any;
+  let SampleResolverClass: any;
+
+  beforeEach(async () => {
+    getMetadataStorage().clear();
+
+    @ObjectType()
+    class SampleObject {
+      @Field()
+      normalField: string;
+
+      @Field(type => [String])
+      normalArrayField: string[];
+
+      @Field({ nullable: true })
+      nullableField: string;
+
+      @Field({ nullable: false })
+      nonNullableField: string;
+    }
+    SampleObjectClass = SampleObject;
+
+    @Resolver(of => SampleObject)
+    class SampleResolver {
+      @Query()
+      normalQuery(): string {
+        return "normalQuery";
+      }
+
+      @Query(returns => [String])
+      normalArrayQuery(): string[] {
+        return ["normalArrayQuery"];
+      }
+
+      @Query(type => String, { nullable: true })
+      nullableQuery() {
+        return null;
+      }
+
+      @Query({ nullable: false })
+      nonNullableQuery(): string {
+        return "nonNullableQuery";
+      }
+    }
+    SampleResolverClass = SampleResolver;
+  });
+
+  describe("default behavior", () => {
+    let schemaIntrospection: IntrospectionSchema;
+    let queryType: IntrospectionObjectType;
+    let sampleObjectType: IntrospectionObjectType;
+
+    beforeEach(async () => {
+      ({ schemaIntrospection, queryType } = await getSchemaInfo({
+        resolvers: [SampleResolverClass],
+      }));
+      sampleObjectType = schemaIntrospection.types.find(
+        type => type.name === "SampleObject",
+      ) as IntrospectionObjectType;
+    });
+
+    it("should emit non nullable fields by default", async () => {
+      const normalField = sampleObjectType.fields.find(it => it.name === "normalField");
+      const normalFieldType = normalField!.type as IntrospectionNonNullTypeRef;
+      const normalFieldInnerType = normalFieldType.ofType as IntrospectionNamedTypeRef;
+      expect(normalFieldType.kind).toBe(TypeKind.NON_NULL);
+      expect(normalFieldInnerType.name).toBe("String");
+
+      const normalArrayField = sampleObjectType.fields.find(it => it.name === "normalArrayField");
+      const normalArrayFieldType = normalArrayField!.type as IntrospectionNonNullTypeRef;
+      const normalArrayFieldListType = normalArrayFieldType.ofType as IntrospectionListTypeRef;
+      const normalArrayFieldListElementType = normalArrayFieldListType.ofType as IntrospectionNonNullTypeRef;
+      const normalArrayFieldListElementInnerType = normalArrayFieldListElementType.ofType as IntrospectionNamedTypeRef;
+      expect(normalArrayFieldType.kind).toBe(TypeKind.NON_NULL);
+      expect(normalArrayFieldListType.kind).toBe(TypeKind.LIST);
+      expect(normalArrayFieldListElementType.kind).toBe(TypeKind.NON_NULL);
+      expect(normalArrayFieldListElementInnerType.kind).toBe(TypeKind.SCALAR);
+      expect(normalArrayFieldListElementInnerType.name).toBe("String");
+    });
+
+    it("should emit non nullable queries by default", async () => {
+      const normalQuery = queryType.fields.find(it => it.name === "normalQuery");
+      const normalQueryType = normalQuery!.type as IntrospectionNonNullTypeRef;
+      const normalQueryInnerType = normalQueryType.ofType as IntrospectionNamedTypeRef;
+      expect(normalQueryType.kind).toBe(TypeKind.NON_NULL);
+      expect(normalQueryInnerType.name).toBe("String");
+
+      const normalArrayQuery = queryType.fields.find(it => it.name === "normalArrayQuery");
+      const normalArrayQueryType = normalArrayQuery!.type as IntrospectionNonNullTypeRef;
+      const normalArrayQueryListType = normalArrayQueryType.ofType as IntrospectionListTypeRef;
+      const normalArrayQueryListElementType = normalArrayQueryListType.ofType as IntrospectionNonNullTypeRef;
+      const normalArrayQueryListElementInnerType = normalArrayQueryListElementType.ofType as IntrospectionNamedTypeRef;
+      expect(normalArrayQueryType.kind).toBe(TypeKind.NON_NULL);
+      expect(normalArrayQueryListType.kind).toBe(TypeKind.LIST);
+      expect(normalArrayQueryListElementType.kind).toBe(TypeKind.NON_NULL);
+      expect(normalArrayQueryListElementInnerType.kind).toBe(TypeKind.SCALAR);
+      expect(normalArrayQueryListElementInnerType.name).toBe("String");
+    });
+  });
+
+  describe("nullableByDefault = true", () => {
+    let schemaIntrospection: IntrospectionSchema;
+    let queryType: IntrospectionObjectType;
+    let sampleObjectType: IntrospectionObjectType;
+
+    beforeEach(async () => {
+      ({ schemaIntrospection, queryType } = await getSchemaInfo({
+        resolvers: [SampleResolverClass],
+        nullableByDefault: true,
+      }));
+      sampleObjectType = schemaIntrospection.types.find(
+        type => type.name === "SampleObject",
+      ) as IntrospectionObjectType;
+    });
+
+    it("should emit nullable fields by default", async () => {
+      const normalField = sampleObjectType.fields.find(it => it.name === "normalField")!;
+      const normalFieldType = normalField.type as IntrospectionNamedTypeRef;
+      expect(normalFieldType.name).toBe("String");
+
+      const normalArrayField = sampleObjectType.fields.find(it => it.name === "normalArrayField");
+      const normalArrayFieldType = normalArrayField!.type as IntrospectionListTypeRef;
+      const normalArrayFieldListElementInnerType = normalArrayFieldType.ofType as IntrospectionNamedTypeRef;
+      expect(normalArrayFieldType.kind).toBe(TypeKind.LIST);
+      expect(normalArrayFieldListElementInnerType.kind).toBe(TypeKind.SCALAR);
+      expect(normalArrayFieldListElementInnerType.name).toBe("String");
+    });
+
+    it("should emit nullable queries by default", async () => {
+      const normalQuery = queryType.fields.find(it => it.name === "normalQuery")!;
+      const normalQueryType = normalQuery.type as IntrospectionNamedTypeRef;
+      expect(normalQueryType.name).toBe("String");
+
+      const normalArrayQuery = queryType.fields.find(it => it.name === "normalArrayQuery");
+      const normalArrayQueryType = normalArrayQuery!.type as IntrospectionListTypeRef;
+      const normalArrayQueryListElementInnerType = normalArrayQueryType.ofType as IntrospectionNamedTypeRef;
+      expect(normalArrayQueryType.kind).toBe(TypeKind.LIST);
+      expect(normalArrayQueryListElementInnerType.kind).toBe(TypeKind.SCALAR);
+      expect(normalArrayQueryListElementInnerType.name).toBe("String");
+    });
+
+    it("shouldn't affect explicit nullability options from decorators", async () => {
+      const nullableField = sampleObjectType.fields.find(it => it.name === "nullableField")!;
+      const nullableFieldType = nullableField.type as IntrospectionNamedTypeRef;
+      expect(nullableFieldType.name).toBe("String");
+
+      const nonNullableField = sampleObjectType.fields.find(it => it.name === "nonNullableField")!;
+      const nonNullableFieldType = nonNullableField.type as IntrospectionNonNullTypeRef;
+      const nonNullableFieldInnerType = nonNullableFieldType.ofType as IntrospectionNamedTypeRef;
+      expect(nonNullableFieldType.kind).toBe(TypeKind.NON_NULL);
+      expect(nonNullableFieldInnerType.name).toBe("String");
+
+      const nullableQuery = queryType.fields.find(it => it.name === "nullableQuery")!;
+      const nullableQueryType = nullableQuery.type as IntrospectionNamedTypeRef;
+      expect(nullableQueryType.name).toBe("String");
+
+      const nonNullableQuery = queryType.fields.find(it => it.name === "nonNullableQuery")!;
+      const nonNullableQueryType = nonNullableQuery.type as IntrospectionNonNullTypeRef;
+      const nonNullableQueryInnerType = nonNullableQueryType.ofType as IntrospectionNamedTypeRef;
+      expect(nonNullableQueryType.kind).toBe(TypeKind.NON_NULL);
+      expect(nonNullableQueryInnerType.name).toBe("String");
+    });
+  });
+});