@lankajs/yup

▸ module · yup conveniences

The one package in the family a yup application cannot work without: a synchronous bridge.

A library in the same box. The app imports and calls it; core does not know it exists.

Runs in: the browser, node and React Native — everywhere.

How to use it: GUIDE.md — the user guide, with examples. How to change it: SKILL.md.

Contents

• lankaYupValidator — the synchronous bridge, because yup's Standard Schema is async
• TLankaInferred<S> — schema type inference

Why this package is not optional

Every other package in modules/validators/ exists to make a CHOICE visible: core already accepts the library's schemas and the package is a name. This one is different.

yup does implement Standard Schema — since 1.7.x — but its ~standard.validate is declared async and therefore returns a promise for every schema, valid or not. The framework's validation port is SYNCHRONOUS and refuses a promise loudly, on purpose: a port that answered "fine" to a value it never inspected would let unvalidated data through. So without this package a yup schema cannot be validated by lanka at all — not slowly, not partially: every call throws.

The bridge is validateSync(value, { abortEarly: false }), which yup has had all along. It lives here rather than in core for the same reason the zod 3 bridge does: it is knowledge about a specific library and a specific version, and core knows only the protocol.

What the bridge has to translate

Three things, each found by a test rather than by reading the documentation:

• Paths are bracketed. yup says tags[0].id; ILankaFieldError.path is segments, so it becomes ["tags", 0, "id"] and the message string stays tags.0.id: …, which is how the whole family reads.
• A top-level failure has no path. yup.number().min(18) refusing 3 reports path: undefined, which is the form's ROOT rather than an input named "".
• An async test cannot run synchronously. yup throws a plain Error saying so. Passed through as-is it would reach a consumer as a stray library error; it comes back as the port's own loud refusal instead.

Repository map: ../../../README.md