# @form-engine-ts/zod

Generates a Zod 4 answer validator from a form-engine-ts `FormSchema` while preserving Core-compatible validation issues.

## Install

```bash
pnpm add @form-engine-ts/core @form-engine-ts/zod zod@^4
```

## Quick start

```ts
import type { FormSchema } from "@form-engine-ts/core";
import { createZodFormSchema } from "@form-engine-ts/zod";

const schema: FormSchema = {
  id: "contact",
  version: 1,
  title: "Contact",
  fields: [{ id: "name", type: "text", title: "Name", required: true }]
};

const result = createZodFormSchema(schema).safeParse({ name: "Ada" });
```

Generate a validator for one wizard page while preserving passthrough values from other pages:

```ts
const firstPageResult = createZodFormSchema(schema, { pageIndex: 0 }).safeParse(values);
```

Zod is a `^4.0.0` peer dependency. Schema metadata is checked by Core before validator creation, and parsed answer
objects retain passthrough values. Required, choice, visibility, and page-scoped issue codes match Core validation.

Use `createZodFormCodec(schema, options)` for a validation-and-normalization pipeline. It can trim strings, remove answers
for currently hidden fields, and strip fields that are not defined by the schema:

```ts
const codec = createZodFormCodec(schema, {
  trimStrings: true,
  stripHiddenFields: true,
  stripUnknownFields: true
});
const normalized = codec.parse(values);
```

When the schema retains literal field IDs (for example with `as const satisfies FormSchema`), the codec's parsed data
is typed as `FormValuesForSchema<typeof schema>`, including number, checkbox, and multi-select field value types.