Non nullable properties are generated as possibly undefined

I have an object of a product that has some non nullable properties such as ProductId and price with the following schema generated by swagger

"ProductBasicInfo": {
        "type": "object",
        "properties": {
          "productId": {
            "type": "integer",
            "format": "int32"
          },
          "brand": {
            "type": "string",
            "nullable": true
          },
          "description": {
            "type": "string",
            "nullable": true
          },
          "name": {
            "type": "string",
            "nullable": true
          },
          "price": {
            "type": "number",
            "format": "double"
          }
        },
        "additionalProperties": false
      }

This is the generated contract

export interface ProductBasicInfo {
  /** @format int32 */
  productId?: number;
  brand?: string | null;
  description?: string | null;
  name?: string | null;

  /** @format double */
  price?: number;
}

As you can see, in the generated contract a ? was added to the non nullable properties making their type effectively number | undefined

Is it possible to omit the ? mark for non nullable types?

[HansFalkenberg-Visma]

What @remkoboschker said is correct. The issue here seems to be the API specification, not this generator.

Unless the name of an OpenApi property is included in the object’s required list, it is an optional property. Optional properties are expressed with ? or undefined in TypeScript.

Nullability is something completely different, namely whether the value of a property that is present may be null. Expressed as null in TypeScript.

I would also recommend simply never using null in TypeScript. The scenarios where it is truly needed are few and far between and the language support for undefined is much better. This works out if any C#/Java implementations – which don’t have a native concept of undefined – treat missing properties as null. If you use both null and undefined in TypeScript and then expect those to be different things (which they totally are!), it likely won’t work out when you meet a C#/Java implementation.

[remkoboschker]

I think the issues is that the open-api spec states that nullable true is a way to say that a property may have the value null. To express that a property may not be undefined would require listing the property as required for that object.