@assassinonz/exzodus-router NPM

ExZodus

ExZodus provides a type-safe Axios client wrapper and an Express router with auto-completion features backed by Zod schemas. This project is heavily inspired by the Zodios project.

Why ExZodus?

The existence of this project is due to following factors.

The wrappers provided by the Zodios project caused heavy TS-Server performance issues leading to Type instantiation is excessively deep and possibly infinite.ts(2589) errors.
The api definition structure required by Zodios seems limited.

Can this replace Zodios?

Absolutely not.

If your workflow didn't encounter above mentioned problems, you should definitely use Zodios. It is well documented and established.
Zodios has many more features that won't be included in the scope of this project.

How to use?

1. Installation

npm i @assassinonz/exzodus

2. Schema definition

Use @kubb/swagger-zod to generate the API schema using an openapi.yaml file or hand write it.
The API schema is typed as follows.

type Path = string;
type Method = string;
type Api = Record<Path, Record<Method, {
    request: z.ZodType | undefined;
    parameters: {
        path: z.ZodType | undefined;
        query: z.ZodType | undefined;
        header: z.ZodType | undefined;
    };
    responses: Record<number | "default", z.ZodType>;
    errors: Record<number, z.ZodType>;
}>>;

An example schema looks as follows.

export const paths = {
    "/users/:id": {
        get: {
            request: undefined,
            parameters: {
                path: z.object({ "id": z.coerce.number.int() }),
                query: undefined,
                header: undefined
            },
            responses: {
                200: z.object({ "id": z.number.int(),  "name": z.string() }),
                404: z.object({ "message": z.string() })
                default: z.object({ "id": z.number.int(),  "name": z.string() })
            },
            errors: {
                404: z.object({ "message": z.coerce.string() })
            }
        },
    }
}

3. Using ExZodusRouter

import { paths } from "../../kubb/zod/operations.js";
import { express, ExZodusRouter } from "@assassinonz/exzodus-router";

//Define context if needed
type Context = {
    userId: number;
}

//                    @kubb/swagger-zod generated API schema
//                                        ▼
const router = ExZodusRouter.new<typeof paths, Context>(paths, {
    //Provide error handler for Zod errors
    errorHandler: (err, req, res) => {
        //TODO: Handle errors
    },

    //Enable response validation to prevent unintentional data leaks
    attachResponseValidator: true
});


//  auto-complete path  fully typed and validated input params (body, query, params)
//             ▼           ▼    ▼
router.get("/users/:id", (req, res) => {
    if (req.ctx === undefined) {
        //Allows only documented response codes
        //Response is typed from the body of 404 response
        //                 ▼
        return res.status(404).json({
            message: "Please login first"
        });
    } else {
        const user = findUserById(req.ctx.userId);

        //Response is typed from the body of 200 response
        //                 ▼
        return res.status(200).json({
            id: user.id,
            name: user.name,
            password: user.password
        });
    }

});


const app = express();
app.use(express.json());
app.use("/api/v1", router);

4. Using ExZodusClient

Calling this API is now easy and has builtin autocomplete features :

import { paths } from "../../kubb/zod/operations.js";
import { ExZodusClient } from "@assassinonz/exzodus-client";


//                @kubb/swagger-zod generated API schema
//                                 ▼
const client = new ExZodusClient(paths, "http://localhost:8080/api/v1");


//   typed                auto-complete path   auto-complete params
//     ▼                           ▼                   ▼
const userResponse = await client.get("/users/:id", { path: { id: 7 } });
console.log(userResponse.data);