composable-functions VS zod

Instead of adding multiple try/catch statements, we'll establish a pattern to deal with exceptions. For that, let me introduce you to Composable Functions, a library we created to make function composition easy and safe.

composable-functions

Last week, I started a Twitter thread about this and asked for help from some friends and TS experts. I was working on our library composable-functions on an issue by @danielweinmann that was experiencing this problem.

As already mentioned dnt might help you if you are willing to have deno as your primary development environment. I work in a project like this and the deno tooling is great. I don't even need a package.json since dnt will generate it for me.

This post shows how to build a small todo MCP server with Node.js using the official @modelcontextprotocol/sdk package and Zod schemas.

This pattern works cleanly with Zod and React Hook Form. Zod schemas can infer TypeScript types directly, so you define validation rules and get the type for free:

Zod closes that gap by validating shape at runtime. The friction is hand-writing the schema. So I built a small in-browser tool that does it for you — paste a JSON sample, get a runnable z.object. This post is about the four non-obvious algorithm choices that came out of that build.

Libraries like React Hook Form, Formik, and Zod for schema validation make the per-step validation architecture manageable and well-tested. React and other component-based frameworks make the state sharing pattern clean with context or a global store.

5. Add runtime validation. Use Zod or Valibot to validate that the API actually sends what your types describe. The converter gives you structure; a schema library gives you runtime guarantees.

When writing runtime validation in TypeScript, Zod is usually the first choice.

Do you validate the data your backend API returns? Most people just use as to cast the type and hope the data matches expectations. Zod lets you define a schema once and get both runtime validation and TypeScript types — no more trust-based programming.

Zod is a TypeScript-first schema declaration and validation library. It is widely used in Next.js projects to bridge the gap between runtime data validation and compile-time type safety.

Every serious TypeScript project uses Zod for runtime validation. The team loves it — one schema, end-to-end type inference, parse-don't-validate all the way down. Done, sorted, move on.

This post walks through a pipeline where you define your data shape once as a Zod schema on the backend, and every other layer (API docs, frontend types, React Query hooks) is generated from it automatically using Orval. Change the schema, regenerate, and TypeScript tells you exactly what broke. Across the entire stack.