How can I tell Swagger to include extended or specific models?

I’m submitting a…

[ ] Regression 
[ ] Bug report
[x] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Current behavior

This might be similar to https://github.com/nestjs/swagger/issues/223. I have a web method something like doWork( expression: AbstractExpression). Swagger includes AbstractExpression in Models. I have several subclasses which extend AbstractExpression, like PropertyExpression, StringExpression, etc, just subclasses. When I call my web method I’m wanting to receive a subclass expression like StringExpression.

The problem is that swagger is not including the extended subclasses in the list of Models because they are not directly referenced. How can I tell nestjs/swagger to explicitly include these extra models?

Expected behavior

I would like to be able to explicitly tag a model or tell swagger to include it. Maybe a class decorator for @ApiModel added to the class could tell swagger to include the model.

Minimal reproduction of the problem with instructions

web method doWork( expression: AbstractExpression)

// included because its referenced
export class AbstractExpression {
	@ApiModelProperty({ description: 'An Abstract class never used direclty.'})
	public expressionType: ExpressionType;
}

@ApiModel()  // this could tell swagger to include it in Models
export class PropertyExpression extends AbstractExpression {
	@ApiModelProperty({	description: 'A subclass dto to pass web method.'})
	public property: string;
}

*** Swagger will not include PropertyExpression in models.  How can I manually add it?

What is the motivation / use case for changing the behavior?

I have an abstract class and send in subclasses to a method that takes a variety of subclasses.

Environment

Nest version: X.Y.Z

 "@nestjs/core": "6.0.5",
"@nestjs/swagger": "3.0.2",

For Tooling issues:
- Node version: XX  
- Platform:  
node 10, macos

Others:

[kamilmysliwiec]

Correct @loban.

This is available in 4.0.0 https://docs.nestjs.com/recipes/swagger#extra-models

Instead of using @ApiExtraModels, you can also pass extraModels array as a part of SwaggerDocumentOptions

SwaggerModule.createDocument(app, config, {
   extraModels: [.......]
});

[elSuperRiton]

+1