useFormHandler

useFormHandler is our composable to handle forms, it takes one object as optional argument and returns various objects and methods that will allow us to handle our forms.

Props

initialValues:

WARNING

Changing the initialValues will trigger a form reset, this means the formState and the values will return to its initial state.

Values which we use to initialize the form, this is useful when we get an initial value state for the form from an external call.

Example

vue

<template>
    <input v-bind="register('firstName')"> // Should initially be 'John'
    <input v-bind="register('lastName')"> // Should initially be 'Doe'
    <pre>{{values}}</pre> // Should show the initialized values
</template>
<script setup lang="ts">
    import { useFormHandler } from 'vue-form-handler'

    const { register, values } = useFormHandler({
        initialValues: {
            firstName: 'John',
            lastName: 'Doe'
        }
    })
</script>

interceptor:

Function that allows us to intercept any value assignment, accept or deny it and perform operations before and after the assignment happens.

Params

The interceptor will be called passing an object as a parameter with the following:

attribute	type	description
name	`string`	Name of the field that is about to be set
value	`any`	Value of the field that is about to be set
clearError	ClearError	API - clearError
clearField	ClearField	API - clearField
formState	FormState	API - formState
modifiedValues	ModifiedValues	API - modifiedValues
resetField	ResetField	API - resetField
resetForm	ResetForm	API - resetForm
setError	SetError	API - setError
setValue	SetValue	API - setValue
triggerValidation	TriggerValidation	API - triggerValidation
values	`Record<string,any>`	API - values

INFO

As you can see, the interceptor is provided with everything the handler does provide but in a separate context.

Expected return

The interceptor expects a type of boolean or a Promise<boolean>, return true to proceed setting the value and false if the value should not be set.

Example

vue

<template>
    <select v-bind="register('continent')" placeholder="Choose your country">
        <option disabled value=null>Choose your continent</option>
        <option value="AM">America</option>
        <option value="AS">Asia</option>
        <option value="EU">Europe</option>
    </select>
    <select v-bind="register('country')" placeholder="Choose your country">
        <option disabled value=null>Choose your country</option>
        <option value="CAN">Canada</option>
        <option value="USA">United States</option>
        <option value="JAP">Japan</option>
        <option value="CHN">China</option>
        <option value="ESP">Spain</option>
        <option value="DEU">Germany</option>
    </select>
</template>
<script setup lang="ts">
import { useFormHandler } from 'vue-form-handler'

const interceptor = ({ name, clearField }) => {
    if (name === 'continent') {
        clearField('country')
    }
    return true
}

const { register } = useFormHandler({
    interceptor
})
</script>

validate:

Use this function in the case you'd rather perform a custom/different validation when submitting your form

Example

vue

<template @submit.prevent="handleSubmit(successFn)">
    <form>
        <input v-bind="register('firstName')">
        <input v-bind="register('lastName')">
        <input type="number" v-bind="register('age')">
        <input type="submit">
    </form>
</template>
<script setup lang="ts">
    import { useFormHandler } from 'vue-form-handler'
    
    const validation = (values) => values.age && Number(values.age)>=18
    const successFn = (form:Record<string,any>) => {
        console.log({form})
    }

    const { register, handleSubmit } = useFormHandler({
        validation
    })
</script>

validationMode:

This option allows you to configure the validation mode or strategy the handler will follow.

name	type	description
onChange	`string`	Validation will trigger on the change event with each input, and lead to multiple re-renders.
onBlur	`string`	Validation will trigger on the blur event.
onSubmit	`string`	Validation will trigger on the submit event.
always	`string`	Validation will trigger on change and blur events.

WARNING

Using the always validationMode will have a more significant impact on performance.

Return

Type Declarations


export type Interceptor = (
    _: InterceptorParams
) => Promise<boolean> | boolean

export type FormValidation = (
    values: Record<string, any>
) => Promise<boolean> | boolean

export interface FormHandlerParams {
    initialValues?: Record<string, any> 
    | Ref<Record<string, any>> 
    | ComputedRef<Record<string, any>>
    interceptor?: Interceptor
    validate?: FormValidation
    validationMode?: 'onChange' 
    | 'onBlur' 
    | 'onSubmit' 
    | 'always'
}
export interface FormHandlerReturn {
    formState: FormState
    values: Record<string, any>
    clearError: ClearError
    clearField: ClearField
    handleSubmit: HandleSubmit
    modifiedValues: ModifiedValues
    register: Register
    resetField: ResetField
    resetForm: ResetForm
    setError: SetError
    setValue: SetValue
    triggerValidation: TriggerValidation
    unregister: (name: string) => void
}

export type FormHandler = (
    _?: FormHandlerParams
) => FormHandlerReturn

useFormHandler #

Props #

initialValues: #

Example #

interceptor: #

Params #

Expected return #

Example #

validate: #

Example #

validationMode: #

Return #

Type Declarations #

useFormHandler

Props

initialValues:

Example

interceptor:

Params

Expected return

Example

validate:

Example

validationMode:

Return

Type Declarations