# Customizing classes


Using Tailwind with Vue Formulate 2.4

Using the newly customizable classes in Vue Formulate, learn how to leverage the Tailwind CSS utility framework to quickly add custom styling to your forms.

There are 4 ways to change the classes applied to DOM elements inside a FormulateInput:

  1. Use props on a FormulateInput.
  2. Globally via the classes option.
  3. Globally via the baseClasses option.
  4. Manually override the DOM using slots.

In the first two cases, you can use a string, array, or function to define which classes should be applied to a given element (e.g., label) in a given state (e.g., field has validation errors). Each element and state is identified by class key.

# Changing classes with props

Changing classes on a given input is easy. Simply target the class key you’d like to change with a prop named [element class key]-class. To target a state use [element class key]-[state class key]-class.

# Strings (to replace base classes)

Use string values in your class prop to replace any base classes.

  label="The label is using its own class"
<!-- <label class="my-label-class"> -->

# Arrays (to append to base classes)

To append classes to the base classes, use an array in your class prop.

  label="The input wrapping div is using its own class"
<!-- <div class="formulate-input-wrapper my-wrapper-class" /> -->

# Functions

For fine grained control you can use a function. The function will receive 2 arguments, a class context object and an array of base classes generated using the global options.

  label="The element div is using its own class"
  :element-class="(context, classes) => ['my-element-class'].concat(classes)"
<!-- <div class="my-element-class formulate-input-element formulate-input-element--text" /> -->

# Changing classes globally

To globally update which classes are applied to every FormulateInput by default you can update the classes option with an object of class keys.

Similar to modifying classes with props the values in the classes option can be a string, array, or function. Strings overwrite any base classes, arrays are appended to the base classes, and functions allow for fine grained control and can accept a context and baseClasses arguments respectively.

# String

import Vue from 'vue'
import VueFormulate from 'vue-formulate'

Vue.use(VueFormulate, {
  classes: {
    outer: 'mytheme-wrapper',
// All <FormulateInput> will output:
// <div class="mytheme-wrapper">...

# Array

Vue.use(VueFormulate, {
  classes: {
    outer: ['mytheme-wrapper'],
// All <FormulateInput> will output:
// <div class="formulate-input mytheme-wrapper">...

# Function

Vue.use(VueFormulate, {
  classes: {
    outer: (context, classes) => {
      return classes.concat([
// All <FormulateInput> will output:
// <div class="formulate-input mytheme-wrapper mytheme-wrapper--[type]">...

# A custom baseClasses function

For advanced use cases, you can also choose to override the base classes by setting options.baseClasses to your own function. This function will be applied to every class key on every <FormulateInput>. For example, if you wanted to perform a reset of all classes in Vue Formulate you could return an empty array:

Vue.use(VueFormulate, {
  baseClasses: (baseClasses, context) => []

# Class keys

Manipulating classes on DOM elements requires targeting which element you want to add/remove classes on. To allow for precise class targeting, every DOM element is assigned an “element key” which can be used to customize classes.

In addition to “element keys”, Vue Formulate also includes “state keys” that are used to describe a specific state of the input. For example hasErrors is the state key for an input that is currently displaying an error. Classes defined with “state keys” are additive, they do not replace any base classes.

# Element keys

# For inputs

Key Default Description
outer .formulate-input The outermost div wrapper.
wrapper .formulate-input-wrapper A wrapper around the label + interior element.
label .formulate-input-label
The label wrapper and its position (before/after).
element .formulate-input-element
The wrapper around the actual <input> element(s).
input n/a Applied directly to the input DOM element. Not used by default to allow for more flexible cascading.
help .formulate-input-help
Wrapper around the help text.
errors .formulate-input-errors Wrapper around the list of errors.
error .formulate-input-error Wrapper around a single error message.

Chart of element class keys

Some input types have additional class keys that are detailed on their own pages:

# For Forms

Key Default Description
form .formulate-form The form element of a FormulateForm.
form-errors .formulate-form-errors The list (ul) of the FormulateErrors component.
form-error .formulate-form-error A list item (li) of the FormulateErrors component.


When using props to change classes for form errors, the props must be placed on the FormulateForm component. Never use class keys directly on the FormulateErrors component.

# Globally

To define a form key globally, be sure to use camel-case:

Vue.use(VueFormulate, {
  classes: {
    formErrors: 'form-errors'

# State keys

State keys make it easy to add a class for a given input state like when a field has a value. State keys must always be combined with an element key.

Key Description
hasErrors For inputs, when the input is visibly showing errors (if the error-behavior is not live this will be false until the errors are shown). For forms, hasErrors is true if any of it’s inputs are not valid irregardless of their visibility.
hasValue The input has a value.
isValid The input has no errors regardless of the visibility.


You can achieve the same result as a state key by using a function for an element key and appending some values based on state provided in the context. These state keys are a helpful shortcut to the same result.

# Globally

To define a state key globally, combine it camel-case style with an element key.

Vue.use(VueFormulate, {
  classes: {
    labelHasValue: 'has-value'

# Via props

To use a state class key via props, you combine it with a element key (kebab case) [element key]-[state-key]-class. For example, to add a check mark to the label of a field that is valid:

  label="Social Security Number"
  help="Please enter your social security number: XXX-XX-XXXX"
    ['matches', /^\d{3}\-\d{2}\-\d{4}$/]
Please enter your social security number: XXX-XX-XXXX

# Class context

Global class functions and prop class functions both receive a “class context” with the following values:

# For inputs

Property Description
attrs Attributes that are applied to the input (ex. disabled)
classification The classification of the input (text, group, select, etc.)
hasErrors Boolean indicating visible errors.
hasValue Boolean whether or not the field has a value.
helpPosition String describing the position of the help text. before or after.
isValid Boolean indicating if the field is error free, regardless of error visibility.
labelPosition String describing the position of the label. before or after.
type The type of input.
value The value of the input.

# For forms

Property Description
attrs Attributes that are applied to the form
classification Always form
errors Form errors from error handling or invalid-message prop.
hasErrors Boolean indicating not all fields are valid (does not account for visibility like the input’s class context).
isLoading The loading state of the form (set with a Promise from the @submit handler)
isValid Inverse of hasErrors.
type Always form.
value The value of the form model