Coerce input with Zod

Set coercion to convert form data and query strings with z.coerce before Zod validates them, and see which format checks each key turns off.

Turn on coercion

Pass true to coerce strings, numbers, and dates, or an object to pick the primitives. See Coercion for primitives in the Zod docs.

import { pluginZod } from '@kubb/plugin-zod'

pluginZod({ coercion: { numbers: true } })

limit: z.int().optional(),

limit: z.coerce.number().int().optional(),

Coerce strings

strings prints string fields as z.coerce.string().

• It replaces the base64, base64url, jwt, ulid, iban, duration, and hostname validators, so Zod no longer checks those formats.
• email, uri, uuid, ipv4, and ipv6 keep their validator and are not coerced.

Coerce numbers

numbers coerces number and integer fields, and enums with a numeric format such as int32.

• Integers typed as number print as z.coerce.number().int(), or z.coerce.number().check(z.int()) with Zod Mini. The coerced call drops the int32 and uint32 range checks.
• format: int64 fields typed as bigint, the adapter default, keep z.coerce.bigint().
• When a coerced enum is the discriminator of a oneOf, the union prints as z.union, because z.discriminatedUnion cannot read coerced values.
• Other enums are not coerced.

Coerce dates

dates coerces only fields typed as Date, which needs dateType: 'date' on the adapter.

• Fields kept as ISO strings are never coerced.
• format: time fields are never coerced, because new Date() cannot parse a bare HH:mm:ss. For a time-of-day type such as Temporal.PlainTime, see Encode custom types.