feat(): add type helpers functions

lib/index.ts

@@ -3,4 +3,5 @@ export * from './decorators';
 export * from './document-builder';
 export * from './interfaces';
 export * from './swagger-module';
+export * from './type-helpers';
 export * from './utils';

lib/type-helpers/index.ts

@@ -0,0 +1,3 @@
+export * from './omit-type.helper';
+export * from './partial-type.helper';
+export * from './pick-type.helper';

lib/type-helpers/omit-type.helper.ts

@@ -0,0 +1,27 @@
+import { Type } from '@nestjs/common';
+import { DECORATORS } from '../constants';
+import { ApiProperty } from '../decorators';
+import { ModelPropertiesAccessor } from '../services/model-properties-accessor';
+
+const modelPropertiesAccessor = new ModelPropertiesAccessor();
+
+export function OmitType<T, K extends keyof T>(
+  classRef: Type<T>,
+  keys: K[]
+): Type<Omit<T, typeof keys[number]>> {
+  const fields = modelPropertiesAccessor
+    .getModelProperties(classRef.prototype)
+    .filter(item => !keys.includes(item as K));
+
+  abstract class OmitTypeClass {}
+
+  fields.forEach(key => {
+    const metadata = Reflect.getMetadata(
+      DECORATORS.API_MODEL_PROPERTIES,
+      classRef.prototype,
+      key
+    );
+    ApiProperty(metadata)(OmitTypeClass.prototype, key);
+  });
+  return OmitTypeClass as Type<Omit<T, typeof keys[number]>>;
+}

lib/type-helpers/partial-type.helper.ts

@@ -0,0 +1,28 @@
+import { Type } from '@nestjs/common';
+import { DECORATORS } from '../constants';
+import { ApiProperty } from '../decorators';
+import { ModelPropertiesAccessor } from '../services/model-properties-accessor';
+
+const modelPropertiesAccessor = new ModelPropertiesAccessor();
+
+export function PartialType<T>(classRef: Type<T>): Type<Partial<T>> {
+  const fields = modelPropertiesAccessor.getModelProperties(classRef.prototype);
+
+  abstract class PartialTypeClass {}
+
+  fields.forEach(key => {
+    const metadata =
+      Reflect.getMetadata(
+        DECORATORS.API_MODEL_PROPERTIES,
+        classRef.prototype,
+        key
+      ) || {};
+
+    ApiProperty({
+      ...metadata,
+      required: false
+    })(PartialTypeClass.prototype, key);
+  });
+
+  return PartialTypeClass as Type<Partial<T>>;
+}

lib/type-helpers/pick-type.helper.ts

@@ -0,0 +1,28 @@
+import { Type } from '@nestjs/common';
+import { DECORATORS } from '../constants';
+import { ApiProperty } from '../decorators';
+import { ModelPropertiesAccessor } from '../services/model-properties-accessor';
+
+const modelPropertiesAccessor = new ModelPropertiesAccessor();
+
+export function PickType<T, K extends keyof T>(
+  classRef: Type<T>,
+  keys: K[]
+): Type<Pick<T, typeof keys[number]>> {
+  const fields = modelPropertiesAccessor
+    .getModelProperties(classRef.prototype)
+    .filter(item => keys.includes(item as K));
+
+  abstract class PickTypeClass {}
+
+  fields.forEach(key => {
+    const metadata = Reflect.getMetadata(
+      DECORATORS.API_MODEL_PROPERTIES,
+      classRef.prototype,
+      key
+    );
+    ApiProperty(metadata)(PickTypeClass.prototype, key);
+  });
+
+  return PickTypeClass as Type<Pick<T, typeof keys[number]>>;
+}

test/type-helpers/omit-type.helper.spec.ts

@@ -0,0 +1,30 @@
+import { Type } from '@nestjs/common';
+import { ApiProperty } from '../../lib/decorators';
+import { ModelPropertiesAccessor } from '../../lib/services/model-properties-accessor';
+import { OmitType } from '../../lib/type-helpers';
+
+describe('OmitType', () => {
+  class CreateUserDto {
+    @ApiProperty({ required: true })
+    login: string;
+
+    @ApiProperty({ minLength: 10 })
+    password: string;
+  }
+
+  class UpdateUserDto extends OmitType(CreateUserDto, ['login']) {}
+
+  let modelPropertiesAccessor: ModelPropertiesAccessor;
+
+  beforeEach(() => {
+    modelPropertiesAccessor = new ModelPropertiesAccessor();
+  });
+
+  it('should omit "login" property', () => {
+    expect(
+      modelPropertiesAccessor.getModelProperties(
+        (UpdateUserDto.prototype as any) as Type<any>
+      )
+    ).toEqual(['password']);
+  });
+});

test/type-helpers/partial-type.helper.spec.ts

@@ -0,0 +1,54 @@
+import { Type } from '@nestjs/common';
+import { DECORATORS } from '../../lib/constants';
+import { ApiProperty } from '../../lib/decorators';
+import { ModelPropertiesAccessor } from '../../lib/services/model-properties-accessor';
+import { PartialType } from '../../lib/type-helpers';
+
+describe('PartialType', () => {
+  class CreateUserDto {
+    @ApiProperty({ required: true })
+    login: string;
+
+    @ApiProperty({ minLength: 10 })
+    password: string;
+  }
+
+  class UpdateUserDto extends PartialType(CreateUserDto) {}
+
+  let modelPropertiesAccessor: ModelPropertiesAccessor;
+
+  beforeEach(() => {
+    modelPropertiesAccessor = new ModelPropertiesAccessor();
+  });
+
+  it('should return partial class', () => {
+    expect(
+      modelPropertiesAccessor.getModelProperties(
+        (UpdateUserDto.prototype as any) as Type<any>
+      )
+    ).toEqual(['login', 'password']);
+  });
+
+  it('should set "required" option to "false" for each property', () => {
+    const classRef = (UpdateUserDto.prototype as any) as Type<any>;
+    const keys = modelPropertiesAccessor.getModelProperties(classRef);
+    const metadata = keys.map(key => {
+      return Reflect.getMetadata(
+        DECORATORS.API_MODEL_PROPERTIES,
+        classRef,
+        key
+      );
+    });
+    expect(metadata[0]).toEqual({
+      isArray: false,
+      required: false,
+      type: String
+    });
+    expect(metadata[1]).toEqual({
+      isArray: false,
+      required: false,
+      minLength: 10,
+      type: String
+    });
+  });
+});

test/type-helpers/pick-type.helper.spec.ts

@@ -0,0 +1,30 @@
+import { Type } from '@nestjs/common';
+import { ApiProperty } from '../../lib/decorators';
+import { ModelPropertiesAccessor } from '../../lib/services/model-properties-accessor';
+import { PickType } from '../../lib/type-helpers';
+
+describe('PickType', () => {
+  class CreateUserDto {
+    @ApiProperty({ required: true })
+    login: string;
+
+    @ApiProperty({ minLength: 10 })
+    password: string;
+  }
+
+  class UpdateUserDto extends PickType(CreateUserDto, ['login']) {}
+
+  let modelPropertiesAccessor: ModelPropertiesAccessor;
+
+  beforeEach(() => {
+    modelPropertiesAccessor = new ModelPropertiesAccessor();
+  });
+
+  it('should pick "login" property', () => {
+    expect(
+      modelPropertiesAccessor.getModelProperties(
+        (UpdateUserDto.prototype as any) as Type<any>
+      )
+    ).toEqual(['login']);
+  });
+});