2021-12-10-advent-calendar-2021-sample4.ts

// .msw/openAPIUtils.ts
import type {
  Endpoints,
  ExampleKind,
  Methods,
  OpenAPISpec,
  ResponseType,
} from "./openAPISpec";

export class OpenAPISpecTools {
  openAPISpec: OpenAPISpec;
  constructor(openAPISpec: OpenAPISpec) {
    this.openAPISpec = openAPISpec;
  }
  getMethodsBy<Path extends Endpoints>(endpoint: Path): Methods[] {
    return Object.keys(this.openAPISpec.paths[endpoint]) as Methods[];
  }
  getExamplesBy<Path extends Endpoints>(path: Path) {
    return <Method extends Methods>(method: Method) =>
      (
        status: string
      ): { [K in ExampleKind<Path, Method>]: ResponseType<Path, Method> } => {
        const response = this.openAPISpec.paths[path][method].responses[status];
        if (response === undefined) {
          throw new Error(`status: ${status} is not defined in path ${path}`);
        }
        const { examples } = response.content["application/json"];
        if (examples === undefined) {
          throw new Error(
            `There are not any examples of ${method} in path ${path}`
          );
        }
        return examples as {
          [K in ExampleKind<Path, Method>]: ResponseType<Path, Method>;
        };
      };
  }
  getExampleNamesBy<Path extends Endpoints>(path: Path) {
    return <Method extends Methods>(method: Method) =>
      (status: string): ExampleKind<Path, Method>[] =>
        Object.keys(this.getExamplesBy(path)(method)(status)) as ExampleKind<
          Path,
          Method
        >[];
  }
  getExampleBy<Path extends Endpoints>(path: Path) {
    return <Method extends Methods>(method: Method) =>
      (status: string) =>
      (exampleKind: ExampleKind<Path, Method>): ResponseType<Path, Method> => {
        // eslint-disable-next-line @typescript-eslint/no-explicit-any
        return (this.getExamplesBy(path)(method)(status) as any)[exampleKind]
          .value;
      };
  }
  isValidExampleNameBy<Path extends Endpoints>(path: Path) {
    return <Method extends Methods>(method: Method) =>
      (status: string) =>
      (
        exampleName: string
      ): exampleName is ReturnType<
        ReturnType<ReturnType<OpenAPISpecTools["getExampleNamesBy"]>>
      >[number] => {
        return (
          exampleName === null ||
          // eslint-disable-next-line @typescript-eslint/no-explicit-any
          this.getExampleNamesBy(path)(method)(status).includes(
            exampleName as any
          )
        );
      };
  }
}