gem-hunter
Language: TypeScript
Generate zod schemas from typescript types/interfaces
Generate Zod schemas (v4) from Typescript types/interfaces.
ts-to-zod now supports Zod v4 with improved performance and enhanced function type handling.
Install ts-to-zod:
$ pnpm add --dev ts-to-zod
Generate Zod schemas from a TypeScript file:
$ pnpm ts-to-zod src/iDontTrustThisApi.ts src/nowIcanValidateEverything.ts
If you're upgrading from Zod v3:
npm install zod@^4npx ts-to-zodThe tool automatically generates code compatible with Zod v4, including updated string validation methods and improved function type support. For Zod-specific breaking changes, see the official Zod v4 changelog.
Note: For Zod v3 support, use ts-to-zod v3.x series.
That's it, go to src/nowIcanValidateEverything.ts file, you should have all the exported interface and type as Zod schemas with the following name pattern: ${originalType}Schema.
Prior to v5, prettier was embedded in the generation process. To make the package leaner and more flexible (maybe you prefer biomejs!), this was removed.
To have the same behavior as before, we can suggest to add pretty-quick after generation process.
--- a/package.json +++ b/package.json - "gen:all": "ts-to-zod --all", + "gen:all": "ts-to-zod --all && pretty-quick",
This will only format the staged files so it’s very fast. Enjoy!
To make sure the generated zod schemas are 100% compatible with your original types, this tool is internally comparing z.infer<generatedSchema> and your original type. If you are running on those validation, please open an issue 😀
Notes:
--skipValidation. (At your own risk!)This tool supports some JSDoc tags (inspired by OpenAPI) to generate additional Zod schema validators.
List of supported keywords:
| JSDoc keyword | JSDoc Example | Generated Zod validator |
|---|---|---|
@minimum {number} [err_msg] |
@minimum 42 |
z.number().min(42) |
@maximum {number} [err_msg] |
@maximum 42 Must be < 42 |
z.number().max(42, "Must be < 42") |
@minLength {number} [err_msg] |
@minLength 42 |
z.string().min(42) |
@maxLength {number} [err_msg] |
@maxLength 42 |
z.string().max(42) |
@format {FormatType} [err_msg] |
@format email |
z.email() |
@pattern {regex} Note: Due to parsing ambiguities, @pattern does not support generating error messages. |
@pattern ^hello |
z.string().regex(/^hello/) |
By default, FormatType is defined as the following type (corresponding Zod validator in comment):
type FormatType = | "date-time" // z.iso.datetime() | "date" // z.iso.date() | "time" // z.iso.time() | "duration" // z.iso.duration() | "email" // z.email() | "ip" // z.ipv4() | "ipv4" // z.ipv4() | "ipv6" // z.ipv6() | "url" // z.url() | "uuid"; // z.uuid()
However, see the section on Custom JSDoc Format Types to learn more about defining other types of formats for string validation.
Those validators can be combined:
// source.ts export interface HeroContact { /** * The email of the hero. * * @format email */ email: string; /** * The name of the hero. * * @minLength 2 * @maxLength 50 */ name: string; /** * The phone number of the hero. * * @pattern ^([+]?d{1,2}[-s]?|)d{3}[-s]?d{3}[-s]?d{4}$ */ phoneNumber: string; /** * Does the hero has super power? * * @default true */ hasSuperPower?: boolean; /** * The age of the hero * * @minimum 0 * @maximum 500 */ age: number; } // output.ts export const heroContactSchema = z.object({ /** * The email of the hero. * * @format email */ email: z.email(), /** * The name of the hero. * * @minLength 2 * @maxLength 50 */ name: z.string().min(2).max(50), /** * The phone number of the hero. * * @pattern ^([+]?d{1,2}[-s]?|)d{3}[-s]?d{3}[-s]?d{4}$ */ phoneNumber: z.string().regex(/^([+]?d{1,2}[-s]?|)d{3}[-s]?d{3}[-s]?d{4}$/), /** * Does the hero has super power? * * @default true */ hasSuperPower: z.boolean().default(true), /** * The age of the hero * * @minimum 0 * @maximum 500 */ age: z.number().min(0).max(500), });
Other JSDoc tags are available:
| JSDoc keyword | JSDoc Example | Description | Generated Zod |
|---|---|---|---|
@description {value} |
@description Full name |
Sets the description of the property | z.string().describe("Full name") |
@default {value} |
@default 42 |
Sets a default value for the property | z.number().default(42) |
@strict |
@strict |
Marks the object as strictObject() |
z.strictObject() |
@schema |
@schema .catch('foo') |
If value starts with a ., appends the specified value to the generated schema. Otherwise this value will override the generated schema. |
z.string().catch('foo') |
| JSDoc keyword | JSDoc Example | Description | Generated Zod |
|---|---|---|---|
@discriminator {propName} |
@discriminator id |
Generates a z.discriminatedUnion() instead of union |
z.discriminatedUnion("id", ...) |
Example:
// source.ts /** * @discriminator type **/ export type Person = | { type: "Adult"; name: string } | { type: "Child"; age: number }; // output.ts // Generated by ts-to-zod import { z } from "zod"; export const personSchema = z.discriminatedUnion("type", [ z.object({ type: z.literal("Adult"), name: z.string(), }), z.object({ type: z.literal("Child"), age: z.number(), }), ]);
Elements of string and number arrays can be validated using the following JSDoc tags (for details see above).
| JSDoc keyword |
|---|
@elementDescription {value} |
@elementMinimum {number} [err_msg] |
@elementMaximum {number} [err_msg] |
@elementMinLength {number} [err_msg] |
@elementMaxLength {number} [err_msg] |
@elementFormat {FormatType} [err_msg] |
@elementPattern {regex} |
Example:
// source.ts export interface EnemyContact { /** * The names of the enemy. * * @elementMinLength 5 * @elementMaxLength 10 * @minLength 2 * @maxLength 50 */ names: string[]; /** * The phone numbers of the enemy. * * @description Include home and work numbers * @elementPattern ^([+]?d{1,2}[-s]?|)d{3}[-s]?d{3}[-s]?d{4}$ */ phoneNumbers: string[]; } // output.ts export const enemyContactSchema = z.object({ /** * The names of the enemy. * * @elementMinLength 5 * @elementMaxLength 10 * @minLength 2 * @maxLength 50 */ name: z.array(z.string().min(5).max(10)).min(2).max(50), /** * The phone numbers of the enemy. * * @elementPattern ^([+]?d{1,2}[-s]?|)d{3}[-s]?d{3}[-s]?d{4}$ */ phoneNumbers: z .array(z.string().regex(/^([+]?d{1,2}[-s]?|)d{3}[-s]?d{3}[-s]?d{4}$/)) .describe("Include home and work numbers"), });
If you want to customize the schema name or restrict the exported schemas, you can do this by adding a ts-to-zod.config.js at the root of your project.
Just run pnpm ts-to-zod --init and you will have a ready to use configuration file (with a bit of type safety).
You have two ways to restrict the scope of ts-to-zod:
nameFilter will filter by interface/type namejsDocTagFilter will filter on jsDocTagExample:
// ts-to-zod.config.js /** * ts-to-zod configuration. * * @type {import("./src/config").TsToZodConfig} */ module.exports = [ { name: "example", input: "example/heros.ts", output: "example/heros.zod.ts", jsDocTagFilter: (tags) => tags.map((tag) => tag.name).includes("toExtract"), // <= rule here }, ]; // example/heros.ts /** * Will not be part of `example/heros.zod.ts` */ export interface Enemy { name: string; powers: string[]; inPrison: boolean; } /** * Will be part of `example/heros.zod.ts` * @toExtract */ export interface Superman { name: "superman" | "clark kent" | "kal-l"; enemies: Record<string, Enemy>; age: number; underKryptonite?: boolean; }
Please note: if your exported interface/type have a reference to a non-exported interface/type, ts-to-zod will not be able to generate anything (missing dependencies will be reported).
ts-to-zod already supports converting several @format types such as email and ip to built-in Zod string validation functions. However, the types supported out of the box are only a subset of those recognized by the OpenAPI specification, which doesn't fit every use case. Thus, you can use the config file to define additional format types using the customJSDocFormatTypes property like so:
{ "customJSDocFormatTypes": { [formatTypeNoSpaces]: | string | {regex: string, errorMessage: string} } }
Here is an example configuration:
{
"customJSDocFormatTypes": {
"phone-number": "^\\d{3}-\\d{3}-\\d{4}$",
"date": {
"regex": "^\\d{4}-\\d{2}-\\d{2}$",
"errorMessage": "Must be in YYYY-MM-DD format."
}
}
}As a result, ts-to-zod will perform the following transformation:
| TypeScript | Zod |
|---|---|
interface Info { /** * @format date */ birthdate: string; /** * @format phone-number Must be a valid phone number. */ phoneNumber: string; } |
const infoSchema = z.object({ /** * @format date */ birthdate: z .string() .regex(/^\d{4}-\d{2}-\d{2}$/, "Must be in YYYY-MM-DD format."), /** * @format phone-number */ phoneNumber: z .string() .regex(/^\d{3}-\d{3}-\d{4}$/, "Must be a valid phone number."), }); |
Since we are generating Zod schemas, we are limited by what Zod actually supports:
To resume, you can use all the primitive types and some the following typescript helpers:
Record<>Pick<>Omit<>Partial<>Required<>Array<>Promise<>This utility is designed to work with one file at a time (it will not split one file into several), and will handle references to types from the same file:
// source.ts export type Id = string; export interface Hero { id: Id; name: string; } // output.ts export const idSchema = z.string(); export const heroSchema = z.object({ id: idSchema, name: z.string(), });
ts-to-zod can reference imported types from other modules but will use an any validation as placeholder, as we cannot know
their schema.
// source.ts import { Person } from "@3rdparty/person"; import { Villain } from "./villain"; export interface Hero { name: string; realPerson: Person; nemesis: Villain; } // output.ts const personSchema = z.any(); const villainSchema = z.any(); export const heroSchema = z.object({ name: z.string(), realPerson: personSchema, nemesis: villainSchema; });
If an imported type is referenced in the ts-to-zod.config.mjs config (as input), this utility will automatically replace the import with the given output from the file, resolving the relative paths between both.
//ts-to-zod.config.mjs /** * ts-to-zod configuration. * * @type {import("./src/config").TsToZodConfig} */ module.exports = [ { name: "villain", input: "src/villain.ts", output: "src/generated/villain.zod.ts", getSchemaName: (id) => `z${id}` }, { name: "hero", input: "src/example/heros.ts", output: "src/example/heros.zod.ts", }, ]; // heros.ts (input) import { Person } from "@3rdparty/person"; import { Villain } from "../villain"; export interface Hero { name: string; realPerson: Person; nemesis: Villain; } // heros.zod.ts (output) import { zVillain } from "../generated/villain.zod"; const personSchema = z.any(); export const heroSchema = z.object({ name: z.string(), realPerson: personSchema, nemesis: zVillain; });
You need more than one file? Want even more power? No problem, just use the tool as a library.
High-level function:
generate take a sourceText and generate two file gettersPlease have a look to src/core/generate.test.ts for more examples.
Low-level functions:
generateZodSchema help you to generate export const ${varName} = ${zodImportValue}.object(…)generateZodInferredType help you to generate export type ${aliasName} = ${zodImportValue}.infer<typeof ${zodConstName}>generateIntegrationTests help you to generate a file comparing the original types & zod typesTo learn more about those functions or their usages, src/core/generate.ts is a good starting point.
$ git clone
$ cd ts-to-zod
$ pnpm install
$ pnpm build
$ ./bin/run
USAGE
$ ts-to-zod [input] [output]
...You also have plenty of unit tests to play safely:
$ pnpm testAnd a playground inside example, buildable with the following command:
$ pnpm gen:example
Last note, if you are updating src/config.ts, you need to run pnpm gen:config to have generate the schemas of the config (src/config.zod.ts) (Yes, we are using the tool to build itself #inception)
Have fun!