To enable graphQL in your nestjs api, you can first read the offical document here.
Step 1, install npm package need
yarn add @nestjs/graphql graphql-tools graphql graphql-type-json apollo-server-express
declare a simple factory class for graphQL
In app.module.ts, add GraphQL module
and also define .gql under schema
Next, create order.resolver.ts which make graphQL support same request as restful, which define in order.controller.
Use postman to make a request for getOrders, we copy the sample request query and variable below
Here is the result which same as using restful API
The sample code is here, hope this help.