use-vest

A Svelte action for Vest, that makes it easy to validate forms and show errors when necessary — built with TypeScript.

Vest, in their own words is a "Declarative validations framework inspired by unit testing libraries".

This svelte action aims to make it easy to use vest in your svelte forms to validate your data and show errors. It will also wrap your call that submits the data to your server and handle any errors that might happen there as well.

See it in action in this Svelte REPL or look at the example in the example.

Installation

npm install --save-prod use-vest
# or pnpmpnp
pnpm add use-vest
# or whatever package manager you like

Usage

Let's assume you have finished writing your suite and have exported the TypeScript type for your FormData (optional).

To see how you would incorporate use-vest in your form, look at the Form.svelte file.

NOTE: Instead of posting all code snippets directly in this README, I decided to use an example/ directory and link to it. This way the example can be type checked, and is actually the source for the unit tests so there is no risk of the documentation being outdated.

As you can see, useVest returns a few stores that hold information about the current state of your form.

But how do the individual input fields get their validation status?

useVest sets up a Svelte context (that is accessible to all children) where everything necessary to display the input field state is stored.

Any input field inside the form simply uses getVestContext() to get the correct context object, and this object will contain the validation result, as well as information about the form in general.

To see how you can use that context, look at Input.svelte and InputError.svelte.