Nest toolkit

Nest utils library

@Output() Decorator

@Output({...}) allows you to customize data returned by the controller layer.
It combines the usage of @SerializeOptions({...}) and @UseInterceptors(...).

For a better understanding of how SerializeOptions and UseInterceptors work, checkout the documentation on the official NestJS Website.

Configuration

To configure the output you can provide 3 properties:

| key | Type | description |
|---|---|---| | class | Function | The decorated DTO Class you want to use. | | transform | TransformOptions? | class-transformer transform options | | validate | ValidationOptions? | class-validator validation options |

Usage

@Output({...}) decorator is a method decorator for controllers only:

    @Get('/:id/endpoint')
    @Output({
        class: ResourceDTO,
        transform: {
            groups: [Groups.Public],
            excludeExtraneousValues: true
        },
        transform: {
            always: true
        }
    })
    public async method(
        @Param('id') id: string,
        @Criteria() criteria?: QueryCriteria<Resource>,
    ): Promise<Resource> {
        criteria = criteria || new QueryCriteria<Resource>({
            survey: { id }
        });

        return await this.resourceService.one(criteria);
    }
}

@Catch Decorator

Default use case

From your custom controller :

class ControllerA {
    get() {
        try {
            // find data
        } catch (e) {
            throw new InternalServerErrorException(e);
        }
    }
}

You can now use the Catch decorator, by default it will map an InternalServerErrorException

class ControllerA {
    @Catch()
    get() {
        // find data
    }
}

Classic use case

From your custom controller :

class ControllerA {
    get() {
        try {
            // find data
        } catch (e) {
            if (e instanceof MyCustomErrorA)
                throw new ConflictException(e);
            if (e instanceof MyCustomErrorB)
                throw new NotFoundException(e);
            throw InternalServerErrorException(e);
        }
    }
}

You can now use the Catch decorator.

class ControllerA {
    @Catch({
        [MyCustomErrorA.name]: ConflictException,
        [MyCustomErrorB.name]: NotFoundException
    })
    get() {
        // find data
    }
}

If MyCustomErrorA is throws, it will be mapped on ConflictException

If MyCustomErrorB is throws, it will be mapped on NotFoundException

Others will be mapped on InternalServerErrorException

Advanced use case

From your custom controller :

class ControllerA {
    get() {
        try {
            // find data
        } catch (e) {
            if (e instanceof MyCustomErrorA) {
                console.log('Show me what you got.');
                throw new ConflictException(e);            
            }
            if (e instanceof MyCustomErrorB)
                throw new NotFoundException(e);
            throw InternalServerErrorException(e);
        }
    }
}

You can now use the Catch decorator.

class HTTPExceptionFactory implements IHttpExceptionFactory {
    public create(e) {
        console.log('Show me what you got.');
        return new ConflictException(e);
    }
}

class ControllerA {
    @Catch({
        [MyCustomErrorA.name]: HTTPExceptionFactory,
        [MyCustomErrorB.name]: NotFoundException
    })
    get() {
        // find data
    }
}

If MyCustomErrorA is throws, it will be mapped on HTTPExceptionFactory and then call the create method. Here you can customize your business rules related to the error.

If MyCustomErrorB is throws, it will be mapped on NotFoundException

Others will be mapped on InternalServerErrorException

Configuration

The second parameter of the decorator takes a CatchOption configuration object with the following properties :

| key | Type | Default | description |
|--------------------------|------------|---------|-------------------------------------------------------------------------------------------------| | reply | Boolean | true | Use an ExceptionFilter to reply to the incoming HttpRequest with the mapped HttpException | | logClientErrorsAsWarning | Boolean | false | Will use logger.warn event for errors mapped to client errors HTTP codes |