feat: Add support for date validation

src/decorators/is-date.spec.ts

@@ -0,0 +1,84 @@
+import { Result } from 'true-myth';
+
+import { input, make, output } from '../../tests/helpers';
+import { IsDate } from '../nestjs-swagger-dto';
+
+describe('IsDate', () => {
+  describe('single date', () => {
+    class Test {
+      @IsDate({ format: 'date' })
+      date!: Date;
+    }
+
+    it('accepts date', async () => {
+      expect(await input(Test, { date: '2011-12-30' })).toStrictEqual(
+        Result.ok(make(Test, { date: new Date('2011-12-30') }))
+      );
+    });
+
+    it('rejects invalid date', async () => {
+      expect(await input(Test, { date: '2011-13-13' })).toStrictEqual(
+        Result.err('date is not a valid Date')
+      );
+
+      expect(await input(Test, { date: 'not a date' })).toStrictEqual(
+        Result.err('date is not formatted as `yyyy-mm-dd`')
+      );
+
+      expect(await input(Test, { date: '2011/12/02' })).toStrictEqual(
+        Result.err('date is not formatted as `yyyy-mm-dd`')
+      );
+    });
+
+    // it('transforms to plain', async () => {
+    //   const dto = make(Test, { booleanField: true });
+    //   expect(output(dto)).toStrictEqual({ booleanField: true });
+    // });
+
+    // it('rejects everything else', async () => {
+    //   const testValues: unknown[] = [
+    //     { booleanField: 'true' },
+    //     { booleanField: 'false' },
+    //     { booleanField: 'abc' },
+    //     { booleanField: 0 },
+    //     { booleanField: [] },
+    //     { booleanField: {} },
+    //     { booleanField: null },
+    //     {},
+    //   ];
+
+    //   for (const testValue of testValues) {
+    //     expect(await input(Test, testValue)).toStrictEqual(
+    //       Result.err('booleanField must be a boolean value')
+    //     );
+    //   }
+    // });
+  });
+
+  describe('single date-time', () => {
+    class Test {
+      @IsDate({ format: 'date-time' })
+      date!: Date;
+    }
+
+    it('accepts date-time', async () => {
+      expect(await input(Test, { date: '2017-06-01T18:43:26.000Z' })).toStrictEqual(
+        Result.ok(make(Test, { date: new Date('2017-06-01T18:43:26.000Z') }))
+      );
+    });
+
+    it('rejects invalid date-time', async () => {
+      expect(await input(Test, { date: '2011-13-13' })).toStrictEqual(
+        Result.err('date is not ISO8601 format')
+      );
+
+      expect(await input(Test, { date: 'not a date' })).toStrictEqual(
+        Result.err('date is not ISO8601 format')
+      );
+
+      expect(await input(Test, { date: '2011/12/02' })).toStrictEqual(
+        Result.err('date is not ISO8601 format')
+      );
+    });
+  });
+});

src/decorators/is-date.ts

@@ -0,0 +1,37 @@
+import { Transform } from 'class-transformer';
+import { IsDate as IsDateCV, isDateString } from 'class-validator';
+
+import { Base, compose, noop } from '../core';
+
+const crudeDateRegex = /^\d{4}-\d{2}-\d{2}$/;
+
+// TODO: array support
+export const IsDate = ({
+  format,
+  ...base
+}: Omit<Base<Date>, 'isArray'> & { format: 'date' | 'date-time' }): PropertyDecorator =>
+  compose(
+    { type: 'string', format },
+    base,
+    format === 'date'
+      ? Transform(({ key, value }) => {
+          if (!crudeDateRegex.test(value)) {
+            return new Error(`${key} is not formatted as \`yyyy-mm-dd\``);
+          }
+
+          const date = new Date(value);
+          if (isNaN(date.getTime())) {
+            return new Error(`${key} is not a valid Date`);
+          }
+
+          return date;
+        })
+      : Transform(({ key, value }) => {
+          if (!isDateString(value, { strict: true })) {
+            return new Error(`${key} is not ISO8601 format`);
+          }
+
+          return new Date(value);
+        }),
+    IsDateCV({ message: ({ value }) => value.message })
+  );

src/nestjs-swagger-dto.ts

@@ -1,5 +1,6 @@
 export * from './decorators/is-boolean';
 export * from './decorators/is-constant';
+export * from './decorators/is-date';
 export * from './decorators/is-enum';
 export * from './decorators/is-nested';
 export * from './decorators/is-number';