Zod Fetch

zod-fetch is a simple API for building a type and runtime-safe fetcher function using Zod schemas.

Usage

Using the default fetcher

You can create a fetcher using createZodFetcher:

import { z } from "zod";
import { createZodFetcher } from "zod-fetch";

const fetchWithZod = createZodFetcher();

fetchWithZod(
  // The schema you want to validate with
  z.object({
    hello: z.literal("world"),
  }),
  // Any parameters you would usually pass to fetch
  "/my-api",
).then((res) => {
  console.log(res);
  //          ^? { hello: string }
});

If you don't pass a fetcher to createZodFetcher, it uses a sensible default fetcher (using the fetch API) to grab the data needed.

Using a custom fetcher

You can pass custom fetchers to createZodFetcher:

import { z } from "zod";
import { createZodFetcher } from "zod-fetch";
import axios from "axios";

const fetchWithZod = createZodFetcher(axios.get);

fetchWithZod(
  z.object({
    data: z.object({
      name: z.string(),
    }),
  }),
  "/user",
  {
    params: {
      id: 12345,
    },
  },
).then((res) => {
  console.log(res);
  //          ^? { data: { name: string } }
});

Why does this exist?

For teams that want to combine runtime-safety with a fetcher (an extremely common use case), you often have a choice:

Use a big, all-encompassing solution like tRPC
Hack something together on your own

I hope that this small API offers a nice compromise for teams looking to bridge that gap. Or, at least, offers some pretty example code you can copy-and-paste into your projects.

Want to learn TypeScript?

zod-fetch only really exists because there's some TypeScript magic required to help zod and fetch knit together nicely.

I cover this TS magic in my TypeScript course, Total TypeScript.