TypeScript Axios Output Does Not Reflect Server-Side DTO Attributes

[sensation61]

I am using NSwag to generate TypeScript (Axios) client code from a Swagger/OpenAPI specification. On the server side, I have Data Transfer Objects (DTOs) with attributes such as [StringLength], [Required], or custom attributes like [Transform]. However, these attributes are not reflected in the generated TypeScript code.

For example, consider the following server-side DTO:

C#

public class ThreadDto
{
    [Required]
    public Guid Id { get; set; }

    [StringLength(50)]
    public string Name { get; set; }

    [Transform("@transform.Type(()=>AssistantDto)")]
    public AssistantDto Assistant { get; set; }
}

When generating TypeScript code, the attributes ([Required], [StringLength], [Transform]) are ignored, and the generated TypeScript class does not include any corresponding decorators or metadata:

Typescript

export class ThreadDto {
    id?: string | null;
    name?: string | null;
    assistant?: AssistantDto | null;
}

This lack of reflection makes it difficult to enforce validation rules or apply custom transformations on the client side.

Expected Behavior:

The attributes defined on the server-side DTOs should be reflected in the generated TypeScript code. For example:

Validation Attributes: Attributes like [Required] or [StringLength] should generate corresponding TypeScript decorators or comments.
Custom Attributes: Custom attributes like [Transform] should be included as metadata or decorators in the generated TypeScript code.
Example of expected output:

export class ThreadDto {
    @IsRequired()
    id!: string;

    @MaxLength(50)
    name?: string | null;

    @transform.Type(()=>AssistantDto)
    assistant?: AssistantDto | null;
}