Idea for a wrapper around Express.js to automatically document API endpoints using Zod. Similar to FastAPI's auto documentation functionality

app.js

const express = require('express');
const { z } = require('zod');
const { generateOpenAPISpec } = require('./openapi-generator');

const app = express();

// Wrapper middleware function
function validateSchema(schema) {
    return function (req, res, next) {
        try {
            schema.parse(req.body); // Validate request body
            schema.parse(req.query); // Validate query parameters
            // You can extend this to validate other parts of the request
            next();
        } catch (error) {
            res.status(400).json({ error: error.message });
        }
    };
}

// Define schemas for routes
const getUserSchema = z.object({
    userId: z.string().uuid(),
});

// Example route with schema validation
app.get('/api/user/:userId', validateSchema(getUserSchema), (req, res) => {
    // Route logic
});

// Generate OpenAPI spec for each route
const openAPISpec = generateOpenAPISpec(app);

// Serve the OpenAPI spec
app.get('/openapi.json', (req, res) => {
    res.json(openAPISpec);
});

app.listen(3000, () => {
    console.log('Server is running on port 3000');
});