Schema mapping

The type in input for each kind of schema:

• z.string(): type="text"
• z.email(), z.url(): type="email", type="url"
• z.iso.date(), z.iso.time(): type="date", type="time"
• z.iso.datetime({ local: true }): type="datetime-local"
• z.coerce.number(): type="number"
• z.boolean(), z.literal(true): type="checkbox"
• z.stringbool(): type="checkbox", with the value a checked box submits
• z.file(): type="file"
• A string with input: "password" metadata: type="password"
• z.enum([…]): no type; spread it onto a <select>
• z.array(z.enum([…])): no type; one checkbox per option
• Anything else (z.uuid(), z.coerce.date(), …): type="text"

Stacking a check such as .regex() on z.email() or z.iso.date() does not change the control type.

Schema constraints become these attributes:

• .min(), .max() on a string: minLength, maxLength
• .regex(): pattern, when it is the only regex and has no flags
• .min(), .max() on a number: min, max
• .multipleOf(): that value as step. .int() alone gives step="1", and neither gives step="any"
• .mime() on a file: accept
• When the schema rejects what an empty control submits: required

This decides both whether required is emitted and what parseForm hands the schema.

• A text control: ""
• An unchecked z.boolean() checkbox: false
• A number, a z.coerce.bigint(), a file or a choice: nothing (undefined)
• An unchecked z.stringbool() box: nothing (undefined)
• A checkbox group with nothing checked: []

These cannot be expressed as HTML attributes, so they are listed in dropped. The server still runs every one.

• A .refine() on the whole schema
• An exclusive bound on a float (.gt(), .lt())
• A regex with flags, and several regexes on one string
• A regex on a control that ignores pattern, such as type="date"
• .mime() on a file, and its size bounds
• .min() on a checkbox group; declare minChecked to run it in the browser too
• Constraints behind a .transform() or a z.custom(), which cannot be read

formFields and parseForm throw, with the reason, on these:

• z.number(), z.bigint(), z.date(), z.literal(1): every value arrives as a string, so nothing could pass. Use z.coerce
• z.record, tuples, nullable objects, a repeat inside a repeat: there is no single name to submit under
• Keys holding . or brackets: they cannot be told apart from the path separators
• z.stringbool().default(true): unchecking the box could never submit false

• Several files in one control. z.array(z.file()) derives repeated single-file rows
• Rules on fields inside repeated rows
• Input masking. Rewriting the value works, but managing the caret is a separate problem from wiring a form