added documentation

src/zodError.ts

@@ -3,6 +3,28 @@
 import type { Request, Response, NextFunction } from 'express'
 import { ZodError } from 'zod'
 
+/**
+ * Zod error handler for express middleware
+ * @param handler Custom error handler function to override default error handler
+ * @returns Express middleware function to handle zod errors
+ *
+ * @example
+ * // Example usage with express
+ * import express from 'express'
+ * import { zodError } from 'express-zod'
+ *
+ * const app = express()
+ *
+ * app.use(zodError())
+ *
+ * // If you want to handle zod errors differently, you can provide a custom error handler
+ * // This custom error handler will override the default error handler
+ * app.use(
+ *   zodError((err, req, res, next) => {
+ *     // Handle zod errors here
+ *   })
+ * )
+ */
 export const zodError = (
   handler?: (
     error: ZodError,
@@ -17,9 +39,13 @@ export const zodError = (
     res: Response,
     next: NextFunction
   ) => {
+    // Check if error is a zod error and handle it accordingly
     if (err instanceof ZodError) {
+      // If custom error handler is provided, use it instead of default error handler
       if (handler) return handler(err, req, res, next)
 
+      // Default error handler for zod errors (returns 400 status code)
+      // You can customize this to return a different status code or error message format if you want
       return res.status(400).json({
         error: {
           message: err.flatten().fieldErrors,

src/zodValidate.ts

@@ -3,12 +3,21 @@
 import type { Request, Response, NextFunction, RequestHandler } from 'express'
 import { z, AnyZodObject } from 'zod'
 
+/**
+ * Validateable interface for express request object
+ */
 interface Validatable {
   body?: Record<string, any>
   params?: Record<string, any>
   query?: Record<string, any>
 }
 
+/**
+ * Validation interface
+ * @template B Zod object for body
+ * @template P Zod object for params
+ * @template Q Zod object for query
+ */
 interface Validation<
   B extends AnyZodObject,
   P extends AnyZodObject,
@@ -19,6 +28,13 @@ interface Validation<
   query?: Q
 }
 
+/**
+ * Validate input with zod object and return parsed object if validation is successful or throw error if validation fails
+ * @param input the input to validate
+ * @param validation the zod object to validate input with´
+ * @returns parsed object if validation is successful
+ * @throws error if validation fails
+ */
 const _validate = async <
   B extends AnyZodObject,
   P extends AnyZodObject,
@@ -40,6 +56,39 @@ const _validate = async <
   }
 }
 
+/**
+ * Express middleware to validate request body, params, and query with zod object and return parsed object if validation is successful or throw error if validation fails
+ *
+ * @param validation Validation object containing zod object for body, params, and query
+ * @returns Express middleware function
+ *
+ * @example
+ *  // Example usage with express
+ *  import express from 'express'
+ *  import { validate } from 'express-zod'
+ *  import { z } from 'zod'
+ *
+ *  const app = express()
+ *
+ *  // Example validation object
+ *  const validation = {
+ *    body: z.object({
+ *      name: z.string(),
+ *    }),
+ *    params: z.object({
+ *      id: z.string(),
+ *    }),
+ *    query: z.object({
+ *      limit: z.number(),
+ *    }),
+ *  }
+ *
+ *  app.post('/users/:id', validate(validation), (req, res) => {
+ *    // req.body.name is now a string
+ *    // req.params.id is now a string
+ *    // req.query.limit is now a number
+ *  })
+ */
 export const validate = <
   B extends AnyZodObject,
   P extends AnyZodObject,