NestJS - ApiProperties not applied by swagger when nested more than 1 level

Question

I'm trying to apply @ApiProperty({ format: "date-time" }) to a nested field in a class. If I do this this at the first level, this works fine. Same If I do it in a field nested within an object. But If I go a level deeper the formatting stops applying in the swagger documentation payload example:

 class testDto {
   @ApiProperty({ format: "date-time" })
   date: string //This works: "2022-09-29T15:28:15.931Z"

   @Type(() => Foo)
   @ValidateNested()
   foo: Foo;
}

 class Foo {
   @ApiProperty({ format: "date-time" })
   date: string //This works: "2022-09-29T15:28:15.931Z"

   @Type(() => Bar)
   @ValidateNested()
   bar: Bar;
}

 class Bar {
   @ApiProperty({ format: "date-time" })
   date: string //This does not work: "string"
}

This will result in a swagger example value that looks something like this:

"date": "2022-09-29T15:28:15.931Z",
"foo": {
    "date": "2022-09-29T15:28:15.931Z",
    "bar": {
      "date": "string"
    }
  }

Is there a way I can make this ApiProperty apply to my nested fields?

looks like a bug to me. You could report that to https://github.com/nestjs/swagger — Micael Levi, Sep 29 '22 at 16:50
[Might be related](https://github.com/nestjs/swagger/issues/724) — Jay McDoniel, Sep 29 '22 at 16:53

score -1 · Answer 1 · answered Dec 06 '22 at 02:29

Solution: You have to specify the ApiProperty type for the parent property For[bar]

 class Foo {
   @ApiProperty({ format: "date-time" })
   date: string

   @Type(() => Bar)
   @ValidateNested()
   @ApiProperty({ type: Bar }) // Tell swagger the type for this property
   bar: Bar;
}

 class Bar {
   @ApiProperty({ format: "date-time" })
   date: string
}

NestJS - ApiProperties not applied by swagger when nested more than 1 level

1 Answers1