Why does NSwag's Typescript Client assert null as any?

[Stan-Stani]

Template code: https://github.com/RicoSuter/NSwag/blob/master/src/NSwag.CodeGeneration.TypeScript/Templates/Client.ProcessResponse.Return.liquid

Generated code looks something like:

 protected processGetById(response: Response): Promise<Thing> {
    const status = response.status
    let _headers: any = {}
    if (response.headers && response.headers.forEach) {
      response.headers.forEach((v: any, k: any) => (_headers[k] = v))
    }
    if (status === 200) {
      return response.text().then((_responseText) => {
        let result200: any = null
        let resultData200 =
          _responseText === ''
            ? null
            : JSON.parse(_responseText, this.jsonParseReviver)
        result200 = Thing.fromJS(resultData200)
        return result200
      })
    } else if (status !== 200 && status !== 204) {
      return response.text().then((_responseText) => {
        return throwException(
          'An unexpected server error occurred.',
          status,
          _responseText,
          _headers
        )
      })
    }
    return Promise.resolve<Thing>(null as any)
  }

Doesn't asserting null as any here defeat the purpose of using TypeScript? Why wouldn't the default TS client type the function as returning Promise<Thing | null>?

When using these clients, we now have to manually remember that the functions can return null despite their TS typings.

Should this behavior be changed?