Why are these properties nullable?

[PierBover]

I'm using NSwag with FastEndpoints in dotnet to generate the OpenAPI spec.

This is the type in the JSON spec:

      "ApiDtosUserDto": {
        "type": "object",
        "additionalProperties": false,
        "properties": {
          "id": {
            "type": "string",
            "format": "guid"
          },
          "email": {
            "type": "string"
          },
          "role": {
            "type": "string"
          }
        }
      },

The properties do not have nullable: true and yet openapi-typescript marks all these properties as nullable in the TS type:

        ApiDtosUserDto: {
            /** Format: guid */
            id?: string;
            email?: string;
            role?: string;
        };

I've been looking at the CLI options and the only setting related to nullable types is --default-non-nullable which is true by default. I've enabled it just in case and the result is the same.

Sorry, this is my first time using OpenAPI... am I missing something very obvious here?

Thanks for any help.

[waynesbrain]

It's because there's no required: [] array that contains the property names in that schema.

[PierBover]

Thanks. Yeah figured it out back then :)

[duncanbeevers]

Thanks @waynesbrain for jumping in.
This is a fiddly spot in our API / documentation, and somewhere we're looking to make improvements in narrowing the API and / or improving the documentation.
For example, oftentimes the presence of the readonly and writeonly properties indicates an alternative schema, not just a twiddling of the property within a specific schema.