How to use zod with fastify

zod-with-fastify.ts

// Firstly you need to set the validator and serializer compiler to the one included in the fastify-type-provider-zod module. (https://fastify.dev/docs/latest/Reference/Validation-and-Serialization/#validation-and-serialization)
// This can be done like:
import {
   serializerCompiler,
   validatorCompiler
} from 'fastify-type-provider-zod';

fastify
   .setValidatorCompiler(validatorCompiler)
   .setSerializerCompiler(serializerCompiler);
//Place this where you create the fastify instance.

// Then for all of the routes you want to use a zod schema with, you simply set the schema to an object. And inside of this object is where you create the zod schema for the different request values, and the responses.
// This is usually how I do my routes:
import { FastifyPluginAsyncZod } from 'fastify-type-provider-zod';
import { z } from 'zod';

export const Example = {
   params: z.object({
      uid: z.string().uuid()
   }),
   querystring: z.object({
      email: z.string().email().toLowerCase()
   }),
   body: z.object({
      termsOfService: z.boolean().default(false)
   }),
   response: {
      // Define your response here:
      200: z.object({
         message: z.string(),
         data: z.object({
            timestamp: z.number(),
            randomString: z.string(),
            randomNumber: z.number()
         })
      })
   }
};

const plugin: FastifyPluginAsyncZod = async (fastify, _opts) => {
   fastify.route({
      url: '/example/:uid',
      method: 'POST',
      schema: Example, // Register the schema
      handler: async (request, _reply) => {
         const { uid } = request.params; // uid: string, is a valid uuid string
         const { email } = request.query; // email: string, is a valid email address in lowercase
         const { termsOfService } = request.body; // termsOfService: boolean, default value is false

         console.log(
            `Processing request with uid: ${uid}, email: ${email}, termsOfService: ${termsOfService}`
         );

         return {
            message: 'Example.',
            data: {
               timestamp: Date.now(),
               randomString: (Math.random() + 1).toString(36).substring(7),
               randomNumber: Math.floor(Math.random() * 100) + 1,

               otherField:
                  'This field will automatically get removed by the serializer'
            }
         };

         /*
            Example of response:

            {
               "message": "Example.",
               "data": {
                  "timestamp": 1722018622440,
                  "randomString": "e8rqdh",
                  "randomNumber": 50
               }
            }


            NOTE: otherField was not included in the response schema, thus not present in the response.
         */
      }
   });
};

export default plugin;