208 lines
6.1 KiB
Markdown
208 lines
6.1 KiB
Markdown
<p align="center">
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<img src="logo.svg" width="200px" align="center" alt="Zod logo" />
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<h1 align="center">Zod</h1>
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<p align="center">
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TypeScript-first schema validation with static type inference
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<br/>
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by <a href="https://x.com/colinhacks">@colinhacks</a>
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</p>
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</p>
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<br/>
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<p align="center">
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<a href="https://github.com/colinhacks/zod/actions?query=branch%3Amain"><img src="https://github.com/colinhacks/zod/actions/workflows/test.yml/badge.svg?event=push&branch=main" alt="Zod CI status" /></a>
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<a href="https://opensource.org/licenses/MIT" rel="nofollow"><img src="https://img.shields.io/github/license/colinhacks/zod" alt="License"></a>
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<a href="https://www.npmjs.com/package/zod" rel="nofollow"><img src="https://img.shields.io/npm/dw/zod.svg" alt="npm"></a>
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<a href="https://discord.gg/KaSRdyX2vc" rel="nofollow"><img src="https://img.shields.io/discord/893487829802418277?label=Discord&logo=discord&logoColor=white" alt="discord server"></a>
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<a href="https://github.com/colinhacks/zod" rel="nofollow"><img src="https://img.shields.io/github/stars/colinhacks/zod" alt="stars"></a>
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</p>
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<div align="center">
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<a href="https://zod.dev/api">Docs</a>
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<span> • </span>
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<a href="https://discord.gg/RcG33DQJdf">Discord</a>
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<span> • </span>
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<a href="https://twitter.com/colinhacks">𝕏</a>
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<span> • </span>
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<a href="https://bsky.app/profile/zod.dev">Bluesky</a>
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<br />
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</div>
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<br/>
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<br/>
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<h2 align="center">Featured sponsor: Jazz</h2>
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<div align="center">
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<a href="https://jazz.tools/?utm_source=zod">
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<picture width="85%" >
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<source media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/garden-co/jazz/938f6767e46cdfded60e50d99bf3b533f4809c68/homepage/homepage/public/Zod%20sponsor%20message.png">
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<img alt="jazz logo" src="https://raw.githubusercontent.com/garden-co/jazz/938f6767e46cdfded60e50d99bf3b533f4809c68/homepage/homepage/public/Zod%20sponsor%20message.png" width="85%">
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</picture>
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</a>
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<br/>
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<p><sub>Learn more about <a target="_blank" rel="noopener noreferrer" href="mailto:sponsorship@colinhacks.com">featured sponsorships</a></sub></p>
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</div>
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<br/>
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<br/>
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<br/>
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### [Read the docs →](https://zod.dev/api)
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<br/>
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<br/>
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## What is Zod?
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Zod is a TypeScript-first validation library. Define a schema and parse some data with it. You'll get back a strongly typed, validated result.
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```ts
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import * as z from "zod";
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const User = z.object({
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name: z.string(),
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});
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// some untrusted data...
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const input = {
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/* stuff */
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};
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// the parsed result is validated and type safe!
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const data = User.parse(input);
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// so you can use it with confidence :)
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console.log(data.name);
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```
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<br/>
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## Features
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- Zero external dependencies
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- Works in Node.js and all modern browsers
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- Tiny: `2kb` core bundle (gzipped)
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- Immutable API: methods return a new instance
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- Concise interface
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- Works with TypeScript and plain JS
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- Built-in JSON Schema conversion
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- Extensive ecosystem
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<br/>
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## Installation
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```sh
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npm install zod
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```
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<br/>
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## Basic usage
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Before you can do anything else, you need to define a schema. For the purposes of this guide, we'll use a simple object schema.
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```ts
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import * as z from "zod";
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const Player = z.object({
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username: z.string(),
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xp: z.number(),
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});
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```
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### Parsing data
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Given any Zod schema, use `.parse` to validate an input. If it's valid, Zod returns a strongly-typed _deep clone_ of the input.
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```ts
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Player.parse({ username: "billie", xp: 100 });
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// => returns { username: "billie", xp: 100 }
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```
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**Note** — If your schema uses certain asynchronous APIs like `async` [refinements](#refine) or [transforms](#transform), you'll need to use the `.parseAsync()` method instead.
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```ts
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const schema = z.string().refine(async (val) => val.length <= 8);
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await schema.parseAsync("hello");
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// => "hello"
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```
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### Handling errors
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When validation fails, the `.parse()` method will throw a `ZodError` instance with granular information about the validation issues.
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```ts
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try {
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Player.parse({ username: 42, xp: "100" });
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} catch (err) {
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if (err instanceof z.ZodError) {
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err.issues;
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/* [
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{
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expected: 'string',
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code: 'invalid_type',
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path: [ 'username' ],
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message: 'Invalid input: expected string'
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},
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{
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expected: 'number',
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code: 'invalid_type',
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path: [ 'xp' ],
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message: 'Invalid input: expected number'
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}
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] */
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}
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}
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```
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To avoid a `try/catch` block, you can use the `.safeParse()` method to get back a plain result object containing either the successfully parsed data or a `ZodError`. The result type is a [discriminated union](https://www.typescriptlang.org/docs/handbook/2/narrowing.html#discriminated-unions), so you can handle both cases conveniently.
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```ts
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const result = Player.safeParse({ username: 42, xp: "100" });
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if (!result.success) {
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result.error; // ZodError instance
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} else {
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result.data; // { username: string; xp: number }
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}
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```
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**Note** — If your schema uses certain asynchronous APIs like `async` [refinements](#refine) or [transforms](#transform), you'll need to use the `.safeParseAsync()` method instead.
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```ts
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const schema = z.string().refine(async (val) => val.length <= 8);
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await schema.safeParseAsync("hello");
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// => { success: true; data: "hello" }
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```
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### Inferring types
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Zod infers a static type from your schema definitions. You can extract this type with the `z.infer<>` utility and use it however you like.
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```ts
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const Player = z.object({
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username: z.string(),
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xp: z.number(),
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});
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// extract the inferred type
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type Player = z.infer<typeof Player>;
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// use it in your code
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const player: Player = { username: "billie", xp: 100 };
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```
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In some cases, the input & output types of a schema can diverge. For instance, the `.transform()` API can convert the input from one type to another. In these cases, you can extract the input and output types independently:
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```ts
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const mySchema = z.string().transform((val) => val.length);
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type MySchemaIn = z.input<typeof mySchema>;
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// => string
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type MySchemaOut = z.output<typeof mySchema>; // equivalent to z.infer<typeof mySchema>
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// number
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```
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