Nest Legacy

As part of the v3.26.0 we released the new SingleHandler
and MultiHandler
approaches to implementing your API contracts.
We don't have any immediate plans to deprecate the old approach, but we do recommend using the new approach as it is more flexible and allows for more control over your API implementation.
If we do make a v4 release, we will likely deprecate the old approach.
::: ## Installation
- pnpm
- npm
- yarn
pnpm add @ts-rest/nest
npm install @ts-rest/nest
yarn add @ts-rest/nest
Usage​
As opposed to the Express implementation, where we can infer types from a function signature, we need to explicitly define our types since Nest controllers are implemented as classes.
import {
nestControllerContract,
NestControllerInterface,
NestRequestShapes,
TsRest,
TsRestRequest,
} from '@ts-rest/nest';
const c = nestControllerContract(apiBlog);
type RequestShapes = NestRequestShapes<typeof c>;
@Controller()
export class PostController implements NestControllerInterface<typeof c> {
constructor(private readonly postService: PostService) {}
@TsRest(c.getPost)
async getPost(@TsRestRequest() { params: { id } }: RequestShapes['getPost']) {
const post = await this.postService.getPost(id);
if (!post) {
return { status: 404 as const, body: null };
}
return { status: 200 as const, body: post };
}
}
The nestControllerContract
filters your contract to only include immediate routes and no nested routes. Otherwise, you'd have to implement the entire contract in a single controller. As a result, it's good practice to design your contract into multiple nested contracts, one for each controller.
To implement a nested contract, you can simply call nestControllerContract(contract.nestedContract)
Having the controller class implement NestControllerInterface
ensures that your controller implements all the routes defined in the contract. In addition, it ensures the type safety of the responses returned.
The @TsRest
decorator takes the route, defines the path and method for the controller route and also configures ts-rest options.
The @TsRestRequest
decorator takes the contract route defined in the @Api
decorator, and returns the parsed and validated (if using Zod) request params, query and body.
As Typescript cannot infer class method parameter types from an implemented interface, we need to explicitly define the type for the request parameter using the NestRequestShapes
type.
Configuration​
To configure certain ts-rest options you can use the @TsRest
decorator on either your Controller or use the existing @Api
decorator.
JSON Query Parameters​
To handle JSON query parameters, pass the jsonQuery
option to the @TsRest
decorator on your entire controller.
@Controller()
@TsRest({ jsonQuery: true })
export class PostController implements NestControllerInterface<typeof c> {}
You can also use the method decorator to override or configure options for a specific route.
@Controller()
@TsRest({ jsonQuery: true })
export class PostController implements NestControllerInterface<typeof c> {
constructor(private readonly postService: PostService) {}
@TsRest(s.route.getPost, { jsonQuery: false })
async getPost(@TsRestRequest() { params: { id } }: RequestShapes['getPost']) {
// ...
}
}
Response Validation​
You can enable response validation by passing the validateResponses
option to the @TsRest()
decorator.
This will enable response parsing and validation for a returned status code, if there is a corresponding response Zod schema defined in the contract.
This is useful for ensuring absolute safety that your controller is returning the correct response types as well as stripping any extra properties.
@Controller()
@TsRest({ validateResponses: true })
export class PostController implements NestControllerInterface<typeof c> {}
If validation fails a ResponseValidationError
will be thrown causing a 500 response to be returned.
You can catch this error and handle it as you wish by using a NestJS exception filter.
Explicit Response Type Safety​
In cases where you do not want to implement NestControllerInterface
.
Say, if you were to implement a contract's non-nested routes across multiple controllers, or use different class method names than the ones defined in your contract, you can still ensure type safety of the responses by using the NestResponseShapes
type.
import {
Api,
nestControllerContract,
NestRequestShapes,
NestResponseShapes,
TsRestRequest,
} from '@ts-rest/nest';
const c = nestControllerContract(apiBlog);
type RequestShapes = NestRequestShapes<typeof c>;
type ResponseShapes = NestResponseShapes<typeof c>;
@Controller()
export class PostController {
constructor(private readonly postService: PostService) {}
@TsRest(c.getPost)
async getPost(
@TsRestRequest() { params: { id } }: RequestShapes['getPost']
): Promise<ResponseShapes['getPost']> {
const post = await this.postService.getPost(id);
if (!post) {
return { status: 404 as const, body: null };
}
return { status: 200 as const, body: post };
}
}
Currently any existing Nest global prefix, versioning, or controller prefixes will be ignored, please see https://github.com/ts-rest/ts-rest/issues/70 for more details.
If this feature is highly requested, we can investigate a solution.
We have added the ability to prefix paths, allowing more flexibility in defining your API endpoints. This can be used as a workaround for this functionality.