svelte-formify
v1.1.16
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A library to manage and validate the forms. This library uses decorators to define validations.
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svelte-formify
A library to manage and validate the forms. This library uses decorators to define validations.
This project is still under development, be careful if you decide to use on a production environment
Installation
npm i svelte-formify
Components
This library provides 3 main core components:
@Field
to define properties and validationsSvelteForm
to manage form state, get errors and the validated input values<FormField>
a simple input field to use and prevents boilerplate codes while create input fields
@Field
Field decorator expects the declarations from yup
library, you can nest any yup validation function while creating
a Field.
Important: We must pass the Type explicitly for nested types. ESBuild does not support emitDecoratorMetadata yet.
Usage example:
import { number, object, string } from 'yup'
import { Field } from 'svelte-formify'
export class Role {
@Field(string().required().oneOf(['admin', 'test'])) name: string
}
export class User {
@Field(string().required()) username: string
@Field(string().required()) password: string
@Field(string().required()) firstName: string
@Field(string().required()) lastName: string
@Field(object(), Role) role: Role // due to a restriction on ESBuild we can not emit decorator metadata for now, therefore we must pass the type for nested values explicitly
}
SvelteForm
SvelteForm class encapsulates the validations, listens for input changes and updates the errors so you can show validates states interactively to the user.
SvelteForm expect 2 parameters while constructing it.
- target: class defines the validation properties
- initialValues: initial values for this class
SvelteForm stores all data in a Context
class. A context contains the properties described as below:
- error : ValidationError thrown by yup validation
- touched true on blur otherwise false
- dirty if user is typing
- value the value typed by user
How get raw values
You can call getRawValues
function if you need the raw values (e.g. : sending the form)
const values = form.getRawValues()
Listening validation result
You can use isValid
property which is a Writable to get validation status each time after user changes something.
Example: you want to enable/disable a button depends on validation status:
<script lang="ts">
import { SvelteForm } from 'svelte-formify'
import { User } from './models/user' // your model classes
const {isValid,...form} = new SvelteForm<User>(User, {
firstName: '',
lastName: '',
password: '',
role: {
name: 'test'
},
username: 'hasan'
})
</script>
<button disabled={!$isValid}>Login</button>
General usage example
<script lang="ts">
import { SvelteForm } from 'svelte-formify'
import { User } from './models/user' // your model classes
const {values,...form} = new SvelteForm<User>(User, {
firstName: '',
lastName: '',
password: '',
role: {
name: 'test'
},
username: 'hasan'
})
// calling validate manually
form.validate().then(rawValue => {}).catch(validationError => {})
// e.g. usage of listener to get username while user types
$: console.log($values.username.value) // returns the typed value
$: console.log($values.username.error) // returns the error
$: console.log($values.username.touched) // true after onBlur
$: console.log($values.username.dirty) // true while user is typing
</script>
{#if $values.username.error }
<small>show some error</small>
{/if}
<FormField form={form} property={$values.username} classes="w-full p-2" placeholder="Username *" />
<!-- e.g. nested object usage -->
<FormField form={form} property={$values.role.name} classes="w-full p-2" placeholder="Role *" />