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Segmented Control

A Segmented control allows users to make a single selection from multiple exclusive options, providing a visually distinct and intuitive way of interacting with radio inputs.

Properties

Features

  • Syncs with disabled state of fieldset
  • Syncs with form reset events
  • Can programmatically set segmented control value
  • Can programmatically focus and blur segmented control items

Installation

To use segmented control add the radio machine to your project, run the following command in your command line:

npm install @zag-js/radio-group @zag-js/react
# or
yarn add @zag-js/radio-group @zag-js/react

This command will install the framework agnostic radio group logic and the reactive utilities for your framework of choice.

Anatomy

To set up the segmented control correctly, you'll need to understand its anatomy and how we name its parts.

Each part includes a data-part attribute to help identify them in the DOM.

On a high level, the segmented control consists of:

  • Root: The root container for the segmented control
  • Indicator: The element that visually represents the active radio item.
  • Radio: The root container for the each radio item
  • Radio Label: The label that gives the user information on each radio item
  • Radio Hidden Input: The native html input that is visually hidden in each radio item.

Usage

First, import the radio group package into your project

import * as radio from "@zag-js/radio-group"

The radio package exports two key functions:

  • machine — The state machine logic for the radio widget.
  • connect — The function that translates the machine's state to JSX attributes and event handlers.

You'll also need to provide a unique id to the useMachine hook. This is used to ensure that every part has a unique identifier.

Next, import the required hooks and functions for your framework and use the radio machine in your project 🔥

import * as radio from "@zag-js/radio-group"
import { useMachine, normalizeProps } from "@zag-js/react"

const items = [
  { label: "React", value: "react" },
  { label: "Angular", value: "ng" },
  { label: "Vue", value: "vue" },
  { label: "Svelte", value: "svelte" },
]

function Radio() {
  const [state, send] = useMachine(radio.machine({ id: "1" }))

  const api = radio.connect(state, send, normalizeProps)

  return (
    <div {...api.rootProps}>
      <div {...api.indicatorProps} />
      {items.map((opt) => (
        <label key={opt.value} {...api.getItemProps({ value: opt.value })}>
          <span {...api.getItemTextProps({ value: opt.value })}>
            {opt.label}
          </span>
          <input {...api.getItemHiddenInputProps({ value: opt.value })} />
        </label>
      ))}
    </div>
  )
}

Disabling the segmented control

To make a segmented control disabled, set the context's disabled property to true

const [state, send] = useMachine(
  radio.machine({
    disabled: true,
  }),
)

Making the segmented control readonly

To make a segmented control readonly, set the context's readOnly property to true

const [state, send] = useMachine(
  radio.machine({
    readOnly: true,
  }),
)

Setting the initial value

To set the segmented control's initial value, set the context's value property to the value of the radio item to be selected by default

const [state, send] = useMachine(
  radio.machine({
    value: "apple",
  }),
)

Listening for changes

When the segmented control value changes, the onValueChange callback is invoked.

const [state, send] = useMachine(
  radio.machine({
    onValueChange(details) {
      // details => { value: string }
      console.log("segmented control value is:", details.value)
    },
  }),
)

Usage within forms

To use segmented control within forms, use the exposed inputProps from the connect function and ensure you pass name value to the machine's context. It will render a hidden input and ensure the value changes get propagated to the form correctly.

const [state, send] = useMachine(
  radio.machine({
    name: "fruits",
  }),
)

Styling guide

Earlier, we mentioned that each segmented control part has a data-part attribute added to them to select and style them in the DOM.

Indicator

Style the segmented control Indicator through the indicator part.

[data-part="indicator"] {
  /* styles for indicator */
}

Focused State

When the radio input is focused, the data-focus attribute is added to the root and label parts.

[data-part="radio"][data-focus] {
  /* styles for radio focus state */
}

[data-part="radio-label"][data-focus] {
  /* styles for radio label focus state */
}

Disabled State

When the radio is disabled, the data-disabled attribute is added to the root and label parts.

[data-part="radio"][data-disabled] {
  /* styles for radio disabled state */
}

[data-part="radio-label"][data-disabled] {
  /* styles for radio label disabled state */
}

Invalid State

When the radio is invalid, the data-invalid attribute is added to the root and label parts.

[data-part="radio"][data-invalid] {
  /* styles for radio invalid state */
}

[data-part="radio-label"][data-invalid] {
  /* styles for radio label invalid state */
}

Methods and Properties

The segmented control's api provides properties and methods you can use to programmatically read and set the segmented control's value.

  • valuestringThe current value of the radio group
  • setValue(value: string) => voidFunction to set the value of the radio group
  • clearValue() => voidFunction to clear the value of the radio group
  • focus() => voidFunction to focus the radio group
  • getItemState(props: ItemProps) => ItemStateReturns the state details of a radio input

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