Zod

Zod is a TypeScript-first schema declaration and validation library

• declare a validator once and infers static TypeScript type

• libraries adapters like react-hook-form

npm install zod

Requires TypeScript 4.5+ and strict mode in your tsconfig.json

// tsconfig.json
{
  // ...
  "compilerOptions": {
    // ...
    "strict": true
  }
}

Usage

import { z } from "zod";

const User = z.object({
  username: z.string(),
});

User.parse({ username: "Ludwig" });

// extract the inferred type
type User = z.infer<typeof User>;
// { username: string }

Types

Primitatives

import { z } from "zod";

// primitive values
z.string();
z.number();
z.bigint();
z.boolean();
z.date();
z.symbol();

// empty types
z.undefined();
z.null();
z.void(); // accepts undefined

// catch-all types, allows any value
z.any();
z.unknown();

z.never(); // allows no values

z.enum([`development`, `test`, `production`])
 .default(`development`),

Optional

z.object({
    optional: z.string().optional(),
    nullable: z.string().nullable(),
    nullish: z.string().nullish(),
});

{
    optional?: string | undefined;
    nullable: string | null;
    nullish?: string | null | undefined;
}

String Validation

// validations
z.string().max(5);
z.string().min(5);
z.string().length(5);
z.string().email();
z.string().url();
z.string().emoji();
z.string().uuid();
z.string().nanoid();
z.string().cuid();
z.string().cuid2();
z.string().ulid();
z.string().regex(regex);
z.string().includes(string);
z.string().startsWith(string);
z.string().endsWith(string);
z.string().datetime(); // ISO 8601; by default only `Z` timezone allowed
z.string().ip(); // defaults to allow both IPv4 and IPv6

// transforms
z.string().trim(); // trim whitespace
z.string().toLowerCase(); // toLowerCase
z.string().toUpperCase(); // toUpperCase

// added in Zod 3.23
z.string().date(); // ISO date format (YYYY-MM-DD)
z.string().time(); // ISO time format (HH:mm:ss[.SSSSSS])
z.string().duration(); // ISO 8601 duration
z.string().base64();