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Select

A Select component allows users pick a value from predefined options.

Properties

Features

  • Support for selecting a single option
  • Keyboard support for opening the listbox using the arrow keys, including automatically focusing the first or last item.
  • Support for looping keyboard navigation.
  • Support for selecting an option with tab key.
  • Typeahead to allow selecting options by typing text, even without opening the listbox
  • Support for Right to Left direction.

Installation

To use the select machine in your project, run the following command in your command line:

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

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

Anatomy

To set up the select 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 select consists of:

  • Label: The element that labels the select.
  • Trigger: The element that is used to open/close the select.
  • Positioner: The element that positions the select dynamically.
  • Menu: The popup element that contains the options.
  • Option: The option element.
  • OptionGroup: The element used to group options.

Usage

First, import the select package into your project

import * as select from "@zag-js/select"

The select package exports two key functions:

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

You'll 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 select machine in your project 🔥

import * as select from "@zag-js/select"
import { useMachine, normalizeProps, Portal } from "@zag-js/react"
import { useId, useRef } from "react"

export function Select() {
  const [state, send] = useMachine(
    select.machine({
      id: useId(),
    }),
  )

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

  return (
    <>
      <div>
        <label {...api.labelProps}>Label</label>
        <button {...api.triggerProps}>
          <span>{api.selectedOption?.label ?? "Select option"}</span>
        </button>
      </div>

      <Portal>
        <div {...api.positionerProps}>
          <ul {...api.contentProps}>
            {selectData.map(({ label, value }) => (
              <li key={value} {...api.getOptionProps({ label, value })}>
                <span>{label}</span>
                {value === api.selectedOption?.value && "✓"}
              </li>
            ))}
          </ul>
        </div>
      </Portal>
    </>
  )
}

Usage within a form

To use select within a form, you'll need to:

  • Pass the name property to the select machine's context
  • Render a hidden select element using api.selectProps
import * as select from "@zag-js/select"
import { useMachine, normalizeProps, Portal } from "@zag-js/react"
import { useId } from "react"

const selectData = [
  { label: "Nigeria", value: "NG" },
  { label: "Japan", value: "JP" },
  { label: "Korea", value: "KO" },
  { label: "Kenya", value: "KE" },
  { label: "United Kingdom", value: "UK" },
  { label: "Ghana", value: "GH" },
  { label: "Uganda", value: "UG" },
]

export function SelectWithForm() {
  const [state, send] = useMachine(
    select.machine({
      id: useId(),
      name: "country",
    }),
  )

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

  return (
    <div>
      {/* Hidden select */}
      <select {...api.hiddenSelectProps}>
        {selectData.map((option) => (
          <option key={option.value} value={option.value}>
            {option.label}
          </option>
        ))}
      </select>

      {/* Custom Select */}
      <div className="control">
        <label {...api.labelProps}>Label</label>
        <button type="button" {...api.triggerProps}>
          <span>{api.selectedOption?.label ?? "Select option"}</span>
          <CaretIcon />
        </button>
      </div>

      <Portal>
        <div {...api.positionerProps}>
          <ul {...api.contentProps}>
            {selectData.map(({ label, value }) => (
              <li key={value} {...api.getOptionProps({ label, value })}>
                <span>{label}</span>
                {value === api.selectedOption?.value && "✓"}
              </li>
            ))}
          </ul>
        </div>
      </Portal>
    </div>
  )
}

Selecting option on tab key

While navigating the options, pressing the Tab key blurs the select and does nothing. In some cases, you might what the Tabkey to select the currently highlighted option. To enable this behaviour, set selectOnTab to true.

const [state, send] = useMachine(
  select.machine({
    id: useId(),
    selectOnTab: true,
  }),
)

Disabling the select

To disable the select, set the disabled property in the machine's context to true.

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

Disabling an option

To disable an option, pass the disabled property in the api.getOptionProps(...) function. This will make it unselectable via mouse and keyboard, and it will be skipped on keyboard navigation.

//...
<li {...api.getOptionProps({ label, value, disabled: true })}>
  {option.label}
</li>
//...

Close on select

This behaviour ensures that the menu is closed when an option is selected and is true by default. It's only concerned with when an option is selected with pointer, space key or enter key. To disable the behaviour, set the closeOnSelect property in the machine's context to false.

const [state, send] = useMachine(
  select.machine({
    id: useId(),
    closeOnSelect: false,
  }),
)

Looping the keyboard navigation

When navigating with the select using the arrow down and up keys, the select stops at the first and last options. If you need want the navigation to loop back to the first or last option, set the loop: true in the machine's context.

const [state, send] = useMachine(
  select.machine({
    id: useId(),
    loop: true,
  }),
)

Listening for highlight changes

When an option is highlighted with the pointer or keyboard, the highlightedOption property in the machine's context is updated. You can listen for this change and do something with it.

const [state, send] = useMachine(
  select.machine({
    id: useId(),
    onHighlight(details) {
      // details => { label: string, value: string }
      console.log(details)
    },
  }),
)

Listening for selection changes

When an option is selected, the selectedOption property in the machine's context is updated. You can listen for this change and do something with it.

const [state, send] = useMachine(
  select.machine({
    id: useId(),
    onSelect(details) {
      // details => { label: string, value: string }
      console.log(details)
    },
  }),
)

Listening for open and close events

When the select is opened or closed, the onOpen and onClose properties in the machine's context are called. You can listen for these events and do something with it.

const [state, send] = useMachine(
  select.machine({
    id: useId(),
    onOpen() {
      console.log("Select opened")
    },
    onClose() {
      console.log("Select closed")
    },
  }),
)

Usage within dialog

When using the select within a dialog, you'll need to avoid rendering the select in a Portal or Teleport. This is because the dialog will trap focus within it, and the select will be rendered outside the dialog.

Consider designing a portalled property in your component to allow you decide where to render the select in a portal.

Styling guide

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

Open and closed state

When the select is open, the trigger and content is given a data-state attribute.

[data-part="trigger"][data-state="open|closed"] {
  /* styles for open or closed state */
}

[data-part="content"][data-state="open|closed"] {
  /* styles for open or closed state */
}

Selected state

When an option is selected, it is given a data-selected attribute.

[data-part="option"][data-selected] {
  /* styles for selected state */
}

Highlighted state

When an option is higlighted, via keyboard navigation or pointer, it is given a data-focus attribute.

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

Invalid state

When the select is invalid, the label and trigger is given a data-invalid attribute.

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

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

Disabled state

When the select is disabled, the trigger and label is given a data-disabled attribute.

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

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

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

Optionally, when an option is disabled, it is given a data-disabled attribute.

Empty state

When no option is selected, the trigger is given a data-placeholder-shown attribute.

[data-part="trigger"][data-placeholder-shown] {
  /* styles for empty select state */
}

Methods and Properties

The select's api exposes the following methods:

  • isOpenbooleanWhether the select is open
  • highlightedOptionOptionThe currently highlighted option
  • selectedOptionOptionThe currently selected option
  • focus() => voidFunction to focus the select
  • open() => voidFunction to open the select
  • close() => voidFunction to close the select
  • setSelectedOption(value: Option) => voidFunction to set the selected option
  • setHighlightedOption(value: Option) => voidFunction to set the highlighted option
  • clearSelectedOption() => voidFunction to clear the selected option
  • getOptionState(props: OptionProps) => { isDisabled: boolean; isHighlighted: boolean; isChecked: boolean; }Returns the state details of an option

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