vue-final-form

Introduction

🏁 High performance subscription-based form state management for Vue.js.

Install

yarn add final-form vue-final-form

Usage

This library exports two components:

import { FinalForm, FinalField } from "vue-final-form";

The first component you'll need is the FinalForm component:

<FinalForm :submit="submit">
  <!-- ignore the children for now -->
</FinalForm>

The only required prop is submit, it defines how to submit the form data, maybe simply log it:

function submit(values) {
  console.log(values);
}

The rendered output is:

<div></div>

As you can see it does nothing for now, you need to feed it a <form>:

<FinalForm :submit="submit">
  <form v-slot="props" @submit="props.handleSubmit">
    <!-- ignore the children for now -->
  </form>
</FinalForm>

Now it renders:

<div><form></form></div>

Here it uses the scoped slots feature from Vue.js (>=2.1.0), props.handleSubmit is the actual method it will run to submit data.

Next let's define a form field with <FinalField> component:

<FinalForm :submit="submit">
  <form v-slot="props" @submit="props.handleSubmit">
    <FinalField
      name="username"
      :validate="v => v ? null : 'this is required'">
      <div v-slot="props">
        <input v-on="props.events" :name="props.name">
        <span v-if="props.meta.error && props.meta.touched">
          {{ props.meta.error }}
        </span>
      </div>
    </FinalField>
  </form>
</FinalForm>

Things got a bit more complex, but it's easy if you try to understand:

The only prop that is required by FinalField is name, it tells the field where to store the field data in the form state, here we stores it as state.username.

The validate prop is used to validate the field data, it could be a function that returns an error message or null, undefined when it's considered valid.

The data that FinalField passed to its children contains props.events which is required to be bound with the input element in order to properly track events. And props.name is the name you gave FinalField, props.meta is some infomation about this field.

API

<FinalForm>

Props

submit

Type: function Default: () => {}

Here we allow submit to be optional since you may not need it when you just use vue-final-form as a form validation tool.

See onSubmit.

validate

Type: function Array<function>

A whole-record validation function that takes all the values of the form and returns any validation errors.

See validate.

initialValues

Type: object

See initialValues.

subscription

Type: FormSubscription Default: All

See FormSubscription.

Events

change

Params:

• formState: https://github.com/final-form/final-form#formstate

Scoped slot props

It basically exposes everything in FormState plus follwoings:

handleSubmit

Type: function

The function that you will invoke to submit the form data, you may use it as the :submit event handler on your <form>.

reset

Type: function

See FormApi.reset.

mutators

Type: ?{ [string]: Function }

See FormApi.mutators.

batch

Type: function

See FormApi.batch.

blur

Type: function

See FormApi.blur.

change

Type: function

See FormApi.change.

focus

Type: function

See FormApi.focus

initialize

Type: function

See FormApi.initialize.

<FinalField>

Props

name

Type: string Required: true

The name of this field.

See name.

validate

Type: function Array<function>

A field-level validation function to validate a single field value. Returns an error if the value is not valid, or undefined if the value is valid.

See validate.

subscription

Type: FieldSubscription Default: All

See FieldSubcription.

Events

change

Params:

• fieldState: https://github.com/final-form/final-form#fieldstate

Scoped slot props

It basically exposes FieldState.

name

Type: string

The name of this field.

See FieldState.name

change

Type: function

See FieldState.change

value

Type: any.

The current value of this field. You should probably bind it to :value of input or textarea if you have set initial value for the field.

events

Type: { input: Function, focus: Function, blur: Function }

Bind these event handlers to your input textarea element.

See FieldState.change, FieldState.focus, FieldState.blur.

meta

Type: object

Everything in FieldState except for blur change focus name

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

Author

vue-final-form © EGOIST, Released under the MIT License. Authored and maintained by EGOIST with help from contributors (list).

egoist.moe · GitHub @EGOIST · Twitter @_egoistlily