feat: add defaultsAsNonNull options to composeMongoose method which makes all fields with default values as NonNull in GraphQL Schema

closes #261

Author: nodkz

src/__tests__/github_issues/261-test.ts

@@ -32,7 +32,7 @@ interface IUser extends Document {
 }
 
 const UserModel = mongoose.model<IUser>('User', UserSchema);
-const UserTC = composeMongoose(UserModel, { schemaComposer });
+const UserTC = composeMongoose(UserModel, { schemaComposer, defaultsAsNonNull: true });
 
 schemaComposer.Query.addFields({
   userById: UserTC.mongooseResolvers.findById(),
@@ -61,7 +61,7 @@ describe('issue #261 - Non-nullability for mongoose fields that have a default v
     );
   });
 
-  it('UserTC should have non-null fields if default value is provided', () => {
+  it('UserTC should have non-null fields if default value is provided and option `defaultsAsNonNull`', () => {
     expect(UserTC.toSDL({ deep: true, omitScalars: true })).toBe(dedent`
       type User {
         _id: Int!
@@ -83,6 +83,32 @@ describe('issue #261 - Non-nullability for mongoose fields that have a default v
     `);
   });
 
+  it('UserTC should not have non-null fields which have default values', () => {
+    const UserWithoutDefaultsTC = composeMongoose(UserModel, {
+      schemaComposer: new SchemaComposer(),
+      name: 'UserWithoutDefaults',
+    });
+    expect(UserWithoutDefaultsTC.toSDL({ deep: true, omitScalars: true })).toBe(dedent`
+      type UserWithoutDefaults {
+        _id: Int!
+        name: String
+        age: Float
+        isActive: Boolean
+        analytics: UserWithoutDefaultsAnalytics
+        periods: [UserWithoutDefaultsPeriods]
+      }
+      
+      type UserWithoutDefaultsAnalytics {
+        isEnabled: Boolean
+      }
+      
+      type UserWithoutDefaultsPeriods {
+        from: Float
+        to: Float
+      }
+    `);
+  });
+
   it('check that graphql gets all default values', async () => {
     expect(
       await testFieldConfig({

src/composeMongoose.ts

@@ -25,6 +25,10 @@ export type ComposeMongooseOpts<TContext> = {
     remove?: string[];
   };
   inputType?: TypeConverterInputTypeOpts;
+  /**
+   * You can make fields as NonNull if they have default value in mongoose model.
+   */
+  defaultsAsNonNull?: boolean;
 };
 
 export type GenerateResolverType<TDoc extends Document, TContext = any> = {
@@ -84,7 +88,9 @@ export function composeMongoose<TDoc extends Document, TContext = any>(
   // but do it AFTER input object type generation
   // NonNull fields !== Required field
   // default values should not affect on that input fields became required
-  makeFieldsNonNullWithDefaultValues(tc);
+  if (opts.defaultsAsNonNull) {
+    makeFieldsNonNullWithDefaultValues(tc);
+  }
 
   tc.makeFieldNonNull('_id');