Primitives to build simple, flexible, WAI-ARIA compliant React autocomplete/dropdown/select/combobox components
See the intro blog post and Episode 79 of the Full Stack Radio podcast
react-00d8ff.svg?style=flat-square){kind=icon}
You need an autocomplete/dropdown/select experience in your application and you want it to be accessible. You also want it to be simple and flexible to account for your use cases.
This is a component that controls user interactions and state for you so you can create autocomplete/dropdown/select/etc. components. It uses a render prop which gives you maximum flexibility with a minimal API because you are responsible for the rendering of everything and you simply apply props to what you're rendering.
This differs from other solutions which render things for their use case and then expose many options to allow for extensibility resulting in a bigger API that is less flexible as well as making the implementation more complicated and harder to contribute to.
NOTE: The original use case of this component is autocomplete, however the API is powerful and flexible enough to build things like dropdowns as well.
- Installation
- Usage
- Basic Props
- Advanced Props
- stateChangeTypes
- Control Props
- Children Function
- Event Handlers
- Utilities
- React Native
- Advanced React Component Patterns course
- Examples
- FAQ
- Inspiration
- Other Solutions
- Bindings for ReasonML
- Contributors
- LICENSE
This module is distributed via npm which is bundled with node and
should be installed as one of your project's dependencies:
npm install --save downshift
This package also depends on
reactandprop-types. Please make sure you have those installed as well.
Note also this library supports
preactout of the box. If you are usingpreactthen use the corresponding module in thepreact/distfolder. You can evenimport Downshift from 'downshift/preact'π
import React from 'react'
import {render} from 'react-dom'
import Downshift from 'downshift'
const items = [
{value: 'apple'},
{value: 'pear'},
{value: 'orange'},
{value: 'grape'},
{value: 'banana'},
]
render(
<Downshift
onChange={selection => alert(`You selected ${selection.value}`)}
itemToString={item => (item ? item.value : '')}
>
{({
getInputProps,
getItemProps,
getLabelProps,
getMenuProps,
isOpen,
inputValue,
highlightedIndex,
selectedItem,
}) => (
<div>
<label {...getLabelProps()}>Enter a fruit</label>
<input {...getInputProps()} />
<ul {...getMenuProps()}>
{isOpen
? items
.filter(item => !inputValue || item.value.includes(inputValue))
.map((item, index) => (
<li
{...getItemProps({
key: item.value,
index,
item,
style: {
backgroundColor:
highlightedIndex === index ? 'lightgray' : 'white',
fontWeight: selectedItem === item ? 'bold' : 'normal',
},
})}
>
{item.value}
</li>
))
: null}
</ul>
</div>
)}
</Downshift>,
document.getElementById('root'),
)<Downshift /> is the only component exposed by this package. It doesn't render
anything itself, it just calls the render function and renders that.
"Use a render prop!"!
<Downshift>{downshift => <div>/* your JSX here! */</div>}</Downshift>.
This is the list of props that you should probably know about. There are some advanced props below as well.
function({})| required
This is called with an object. Read more about the properties of this object in the section "Children Function".
function(item: any)| defaults to:i => (i == null ? '' : String(i))
Used to determine the string value for the selected item (which is used to
compute the inputValue).
function(selectedItem: any, stateAndHelpers: object)| optional, no useful default
Called when the user selects an item and the selected item has changed. Called
with the item that was selected and the new state of downshift. (see
onStateChange for more info on stateAndHelpers).
selectedItem: The item that was just selectedstateAndHelpers: This is the same thing yourchildrenfunction is called with (see Children Function)
function(state: object, changes: object)| optional
π¨ This is a really handy power feature π¨
This function will be called each time downshift sets its internal state
(or calls your onStateChange handler for control props). It allows you to
modify the state change that will take place which can give you fine grain
control over how the component interacts with user updates without having to
use Control Props. It gives you the current state and the
state that will be set, and you return the state that you want to set.
state: The full current state of downshift.changes: These are the properties that are about to change. This also has atypeproperty which you can learn more about in thestateChangeTypessection.
const ui = (
<Downshift stateReducer={stateReducer}>{/* your callback */}</Downshift>
)
function stateReducer(state, changes) {
// this prevents the menu from being closed when the user
// selects an item with a keyboard or mouse
switch (changes.type) {
case Downshift.stateChangeTypes.keyDownEnter:
case Downshift.stateChangeTypes.clickItem:
return {
...changes,
isOpen: state.isOpen,
highlightedIndex: state.highlightedIndex,
}
default:
return changes
}
}
any| defaults tonull
Pass an item or an array of items that should be selected by default.
number/null| defaults tonull
This is the initial index to highlight when the menu first opens.
string| defaults to''
This is the initial input value.
boolean| defaults tofalse
This is the initial isOpen value.
function(prevItem: any, item: any)| defaults to:(prevItem, item) => (prevItem !== item)
Used to determine if the new selectedItem has changed compared to the previous
selectedItem and properly update Downshift's internal state.
function({/* see below */})| default messages provided in English
This function is passed as props to a Status component nested within and
allows you to create your own assertive ARIA statuses.
A default getA11yStatusMessage function is provided that will check
resultCount and return "No results." or if there are results but no item is
highlighted, "resultCount results are available, use up and down arrow keys to
navigate." If an item is highlighted it will run itemToString(highlightedItem)
and display the value of the highlightedItem.
The object you are passed to generate your status message has the following properties:
| property | type | description |
|---|---|---|
highlightedIndex |
number/null |
The currently highlighted index |
highlightedItem |
any |
The value of the highlighted item |
inputValue |
string |
The current input value |
isOpen |
boolean |
The isOpen state |
itemToString |
function(any) |
The itemToString function (see props) for getting the string value from one of the options |
previousResultCount |
number |
The total items showing in the dropdown the last time the status was updated |
resultCount |
number |
The total items showing in the dropdown |
selectedItem |
any |
The value of the currently selected item |
function(selectedItem: any, stateAndHelpers: object)| optional, no useful default
Called when the user selects an item, regardless of the previous selected item.
Called with the item that was selected and the new state of downshift. (see
onStateChange for more info on stateAndHelpers).
selectedItem: The item that was just selectedstateAndHelpers: This is the same thing yourchildrenfunction is called with (see Children Function)
function(changes: object, stateAndHelpers: object)| optional, no useful default
This function is called anytime the internal state changes. This can be useful
if you're using downshift as a "controlled" component, where you manage some or
all of the state (e.g. isOpen, selectedItem, highlightedIndex, etc) and then
pass it as props, rather than letting downshift control all its state itself.
The parameters both take the shape of internal state ({highlightedIndex: number, inputValue: string, isOpen: boolean, selectedItem: any}) but differ
slightly.
changes: These are the properties that actually have changed since the last state change. This also has atypeproperty which you can learn more about in thestateChangeTypessection.stateAndHelpers: This is the exact same thing yourchildrenfunction is called with (see Children Function)
Tip: This function will be called any time any state is changed. The best way to determine whether any particular state was changed, you can use
changes.hasOwnProperty('propName').
function(inputValue: string, stateAndHelpers: object)| optional, no useful default
Called whenever the input value changes. Useful to use instead or in combination
of onStateChange when inputValue is a controlled prop to
avoid issues with cursor positions.
inputValue: The current value of the inputstateAndHelpers: This is the same thing yourchildrenfunction is called with (see Children Function)
number| optional, defaults the number of times you call getItemProps
This is useful if you're using some kind of virtual listing component for
"windowing" (like
react-virtualized).
number| control prop (read more about this in the Control Props section)
The index that should be highlighted
string| control prop (read more about this in the Control Props section)
The value the input should have
boolean| control prop (read more about this in the Control Props section)
Whether the menu should be considered open or closed. Some aspects of the
downshift component respond differently based on this value (for example, if
isOpen is true when the user hits "Enter" on the input field, then the item at
the highlightedIndex item is selected).
any/Array(any)| control prop (read more about this in the Control Props section)
The currently selected item.
string| defaults to a generated ID
You should not normally need to set this prop. It's only useful if you're server
rendering items (which each have an id prop generated based on the downshift
id). For more information see the FAQ below.
string| defaults to a generated ID
Used for aria attributes and the id prop of the element (input) you use
getInputProps with.
string| defaults to a generated ID
Used for aria attributes and the id prop of the element (label) you use
getLabelProps with.
string| defaults to a generated ID
Used for aria attributes and the id prop of the element (ul) you use
getMenuProps with.
function(index)| defaults to a function that generates an ID based on the index
Used for aria attributes and the id prop of the element (li) you use
getInputProps with.
window| defaults towindow
You should not normally need to set this prop. It's only useful if you're
rendering into a different window context from where your JavaScript is
running, for example an iframe.
function(stateAndHelpers: object)| optional
A helper callback to help control internal state of downshift like isOpen as
mentioned in this issue. The
same behavior can be achieved using onStateChange, but this prop is provided
as a helper because it's a fairly common use-case if you're controlling the
isOpen state:
const ui = (
<Downshift
isOpen={this.state.menuIsOpen}
onOuterClick={() => this.setState({menuIsOpen: false})}
>
{/* your callback */}
</Downshift>
)This callback will only be called if isOpen is true.
There are a few props that expose changes to state
(onStateChange and stateReducer).
For you to make the most of these APIs, it's important for you to understand
why state is being changed. To accomplish this, there's a type property on the
changes object you get. This type corresponds to a
Downshift.stateChangeTypes property. If you want to see what change types
are available, run this in your app:
console.log(Object.keys(Downshift.stateChangeTypes))downshift manages its own state internally and calls your onChange and
onStateChange handlers with any relevant changes. The state that downshift
manages includes: isOpen, selectedItem, inputValue, and
highlightedIndex. Your Children function (read more below) can be used to
manipulate this state and can likely support many of your use cases.
However, if more control is needed, you can pass any of these pieces of state as
a prop (as indicated above) and that state becomes controlled. As soon as
this.props[statePropKey] !== undefined, internally, downshift will determine
its state based on your prop's value rather than its own internal state. You
will be required to keep the state up to date (this is where onStateChange
comes in really handy), but you can also control the state from anywhere, be
that state from other components, redux, react-router, or anywhere else.
Note: This is very similar to how normal controlled components work elsewhere in react (like
<input />). If you want to learn more about this concept, you can learn about that from this the Advanced React Component Patterns course
This is where you render whatever you want to based on the state of downshift.
You use it like so:
const ui = (
<Downshift>
{downshift => (
// use downshift utilities and state here, like downshift.isOpen,
// downshift.getInputProps, etc.
<div>{/* more jsx here */}</div>
)}
</Downshift>
)The properties of this downshift object can be split into three categories as
indicated below:
NOTE: These prop-getters provide important
aria-attributes which are very important to your component being accessible. It's recommended that you utilize these functions and apply the props they give you to your components.
These functions are used to apply props to the elements that you render. This
gives you maximum flexibility to render what, when, and wherever you like. You
call these on the element in question (for example: <input {...getInputProps()})). It's advisable to pass all your props to that function
rather than applying them on the element yourself to avoid your props being
overridden (or overriding the props returned). For example:
getInputProps({onKeyUp(event) {console.log(event)}}).
| property | type | description |
|---|---|---|
getToggleButtonProps |
function({}) |
returns the props you should apply to any menu toggle button element you render. |
getInputProps |
function({}) |
returns the props you should apply to the input element that you render. |
getItemProps |
function({}) |
returns the props you should apply to any menu item elements you render. |
getLabelProps |
function({}) |
returns the props you should apply to the label element that you render. |
getMenuProps |
function({}) |
returns the props you should apply to the ul element (or root of your menu) that you render. |
getRootProps |
function({},{}) |
returns the props you should apply to the root element that you render. It can be optional. |
If you cannot render a div as the root element, then read this
Most of the time, you can just render a div yourself and Downshift will
apply the props it needs to do its job (and you don't need to call this
function). However, if you're rendering a composite component (custom component)
as the root element, then you'll need to call getRootProps and apply that to
your root element (downshift will throw an error otherwise).
Required properties:
refKey: if you're rendering a composite component, that component will need to accept a prop which it forwards to the root DOM element. Commonly, folks call thisinnerRef. So you'd call:getRootProps({refKey: 'innerRef'})and your composite component would forward like:<div ref={props.innerRef} />
If you're rendering a composite component, Downshift checks that
getRootProps is called and that refKey is a prop of the returned composite
component. This is done to catch common causes of errors but, in some cases, the
check could fail even if the ref is correctly forwarded to the root DOM
component. In these cases, you can provide the object {suppressRefError : true} as the second argument to getRootProps to completely bypass the check.
Please use it with extreme care and only if you are absolutely sure that the ref
is correctly forwarded otherwise Downshift will unexpectedly fail.
See #235 for the discussion that lead to this.
This method should be applied to the input you render. It is recommended that
you pass all props as an object to this method which will compose together any
of the event handlers you need to apply to the input while preserving the ones
that downshift needs to apply to make the input behave.
There are no required properties for this method.
Optional properties:
disabled: If this is set to true, then no event handlers will be returned fromgetInputPropsand adisabledprop will be returned (effectively disabling the input).
This method should be applied to the label you render. It is useful for
ensuring that the for attribute on the <label> (htmlFor as a react prop)
is the same as the id that appears on the input. If no htmlFor is provided
(the normal case) then an ID will be generated and used for the input and the
label for attribute.
There are no required properties for this method.
Note: For accessibility purposes, calling this method is highly recommended.
This method should be applied to the element which contains your list of items.
Typically, this will be a <div> or a <ul> that surrounds a map expression.
This handles the proper ARIA roles and attributes.
Optional properties:
aria-label: By default the menu will add anaria-labelledbythat refers to the<label>rendered withgetLabelProps. However, if you providearia-labelto give a more specific label that describes the options available, thenaria-labelledbywill not be provided and screen readers can use youraria-labelinstead.
<ul {...getMenuProps()}>
{!isOpen
? null
: items.map((item, index) => (
<li {...getItemProps({item, index, key: item.id})}>{item.name}</li>
))}
</ul>Note that for accessibility reasons it's best if you always render this element whether or not downshift is in an
isOpenstate.
The props returned from calling this function should be applied to any menu items you render.
This is an impure function, so it should only be called when you will actually be applying the props to an item.
What do you mean by impure function?
Basically just don't do this:
items.map(item => {
const props = getItemProps({item}) // we're calling it here
if (!shouldRenderItem(item)) {
return null // but we're not using props, and downshift thinks we are...
}
return <div {...props} />
})Instead, you could do this:
items.filter(shouldRenderItem).map(item => <div {...getItemProps({item})} />)Required properties:
item: this is the item data that will be selected when the user selects a particular item.
Optional properties:
index: This is howdownshiftkeeps track of your item when updating thehighlightedIndexas the user keys around. By default,downshiftwill assume theindexis the order in which you're callinggetItemProps. This is often good enough, but if you find odd behavior, try setting this explicitly. It's probably best to be explicit aboutindexwhen using a windowing library likereact-virtualized.disabled: If this is set totrue, then all of the downshift item event handlers will be omitted. Items will not be highlighted when hovered, and items will not be selected when clicked.
Call this and apply the returned props to a button. It allows you to toggle
the Menu component. You can definitely build something like this yourself (all
of the available APIs are exposed to you), but this is nice because it will also
apply all of the proper ARIA attributes.
Optional properties:
disabled: If this is set totrue, then all of the downshift button event handlers will be omitted (it wont toggle the menu when clicked).aria-label: Thearia-labelprop is in English. You should probably override this yourself so you can provide translations:
const myButton = (
<button
{...getToggleButtonProps({
'aria-label': translateWithId(isOpen ? 'close.menu' : 'open.menu'),
})}
/>
)These are functions you can call to change the state of the downshift component.
| property | type | description |
|---|---|---|
clearSelection |
function(cb: Function) |
clears the selection |
clearItems |
function() |
Clears downshift's record of all the items. Only really useful if you render your items asynchronously within downshift. See #186 |
closeMenu |
function(cb: Function) |
closes the menu |
openMenu |
function(cb: Function) |
opens the menu |
selectHighlightedItem |
function(otherStateToSet: object, cb: Function) |
selects the item that is currently highlighted |
selectItem |
function(item: any, otherStateToSet: object, cb: Function) |
selects the given item |
selectItemAtIndex |
function(index: number, otherStateToSet: object, cb: Function) |
selects the item at the given index |
setHighlightedIndex |
function(index: number, otherStateToSet: object, cb: Function) |
call to set a new highlighted index |
toggleMenu |
function(otherStateToSet: object, cb: Function) |
toggle the menu open state |
reset |
function(otherStateToSet: object, cb: Function) |
this resets downshift's state to a reasonable default |
setItemCount |
function(count: number) |
this sets the itemCount. Handy in situations where you're using windowing and the items are loaded asynchronously from within downshift (so you can't use the itemCount prop. |
unsetItemCount |
function() |
this unsets the itemCount which means the item count will be calculated instead by the itemCount prop or based on how many times you call getItemProps. |
setState |
function(stateToSet: object, cb: Function) |
This is a general setState function. It uses downshift's internalSetState function which works with control props and calls your onSelect, onChange, etc. (Note, you can specify a type which you can reference in some other APIs like the stateReducer). |
otherStateToSetrefers to an object to set other internal state. It is recommended to avoid abusing this, but is available if you need it.
These are values that represent the current state of the downshift component.
| property | type | description |
|---|---|---|
highlightedIndex |
number / null |
the currently highlighted item |
inputValue |
string / null |
the current value of the getInputProps input |
isOpen |
boolean |
the menu open state |
selectedItem |
any |
the currently selected item input |
As a convenience, the id and itemToString props which you pass to
<Downshift /> are available here as well.
Downshift has a few events for which it provides implicit handlers. Several of
these handlers call event.preventDefault(). Their additional functionality is
described below.
-
ArrowDown: moves the highlighted index down by 1. If this shift key is held when this event fires, the highlighted index will jump down 5 indices instead of 1. NOTE: if the current highlighed index is within the bottom 5 indices, the top-most index will be highlighted.) -
ArrowUp: moves the highlighted index up by 1. If this shift key is held when this event fires, the highlighted index will jump up 5 indices instead of 1. NOTE: if the current highlighed index is within the top 5 indices, the bottom-most index will be highlighted.) -
Enter: if the menu is open, select the currently highlighted item. If the menu is open, the usual 'Enter' event is prevented by Downshift's default implicit enter handler; so, for example, a form submission event will not work as one might expect (though if the menu is closed the form submission will work normally). See below for customizing the handlers. -
Escape: will reset downshift's state. This means thathighlightedIndexwill be set to thedefaultHighlightedIndex, theinputValuewill be set to theitemToStringvalue of theselectedItem, and theisOpenstate will be set tofalse.
You can provide your own event handlers to Downshift which will be called before the default handlers:
const ui = (
<Downshift>
{({getInputProps}) => (
<input
{...getInputProps({
onKeyDown: event => {
// your handler code
},
})}
/>
)}
</Downshift>
)If you would like to prevent the default handler behavior in some cases, you can set the event's preventDownshiftDefault property to true:
const ui = (
<Downshift>
{({getInputProps}) => (
<input
{...getInputProps({
onKeyDown: event => {
if (event.key === 'Enter') {
// Prevent Downshift's default 'Enter' behavior.
event.nativeEvent.preventDownshiftDefault = true
// your handler code
}
},
})}
/>
)}
</Downshift>
)If you would like to completely override Downshift's behavior for a handler, in favor of your own, you can bypass prop getters:
const ui = (
<Downshift>
{({getInputProps}) => (
<input
{...getInputProps()}
onKeyDown={event => {
// your handler code
}}
/>
)}
</Downshift>
)Allows reseting the internal id counter which is used to generate unique ids for Downshift component.
You should never need to use this in the browser. Only if you are running an universal React app that is rendered on the server you should call resetIdCounter before every render so that the ids that get generated on the server match the ids generated in the browser.
import {resetIdCounter} from 'downshift';
resetIdCounter()
ReactDOMServer.renderToString(...);Since Downshift renders it's UI using render props, Downshift supports rendering on React Native with ease. Use components like <View>, <Text>, <TouchableOpacity> and others inside of your render method to generate awesome autocomplete, dropdown, or selection components.
- Your root view will need to either pass a ref to
getRootPropsor callgetRootPropswith{ suppressRefError: true }. This ref is used to catch a common set of errors around composite components. Learn more ingetRootProps. - When using a
<FlatList>or<ScrollView>, be sure to supply thekeyboardShouldPersistTapsprop to ensure that your text input stays focus, while allowing for taps on the touchables rendered for your items.
Kent C. Dodds has created learning material based on the patterns implemented in this component. You can find it on various platforms:
- egghead.io
- Frontend Masters
- YouTube (for free!): Part 1 and Part 2
Examples exist on codesandbox.io:
- Bare bones autocomplete
- Multiple selection (uses controlled
selectedItemAPI). - Type Ahead Example (uses controlled
selectedItemAPI). - Integration with Apollo
- Integration with Redux
- Integration with
react-instantsearchfrom Algolia - Material-UI (1.0.0-beta.4) Combobox Using Downshift
- Material-UI (1.0.0-beta.33) Multiple select with autocomplete
- Integration with
GenieJS(learn more aboutgeniehere) - Handling and displaying errors
- Integration with React Router
- Windowing with
react-tiny-virtual-list - Section/option group example
- Integration with
fuzzaldrin-plus(Fuzzy matching) - Dropdown/select implementation with Bootstrap
- Multiple editable tag selection
- Downshift implemented as compound components and a Higher Order Component
(exposes a
withDownshifthigher order component which you can use to get at the state, actions, prop getters in a rendered downshift tree). - Downshift Spectre.css example
- Integration with
redux-form - Integration with
react-final-form - Provider Pattern - how to avoid prop-drilling if you like to break up your render method into more components
- React Native example
- React VR example
- Multiple checkbox selection
If you would like to add an example, follow these steps:
- Fork this codesandbox
- Make sure your version (under dependencies) is the latest available version.
- Update the title and description
- Update the code for your example (add some form of documentation to explain what it is)
- Add the tag:
downshift:example
You'll find other examples in the stories/examples folder of the repo. And
you'll find
a live version of those examples here
How do I avoid the checksum error when server rendering (SSR)?
The checksum error you're seeing is most likely due to the automatically
generated id and/or htmlFor prop you get from getInputProps and
getLabelProps (respectively). It could also be from the automatically
generated id prop you get from getItemProps (though this is not likely as
you're probably not rendering any items when rendering a downshift component on
the server).
To avoid these problems, simply call resetIdCounter before
ReactDOM.renderToString.
Alternatively you could provide your own ids via the id props where you render
<Downshift />:
const ui = (
<Downshift
id="autocomplete"
labelId="autocomplete-label"
inputId="autocomplete-input"
menuId="autocomplete-menu"
>
{({getInputProps, getLabelProps}) => <div>{/* your UI */}</div>}
</Downshift>
)I was heavily inspired by Ryan Florence. Watch his (free) lesson about "Compound Components". Initially downshift was a group of compound components using context to communicate. But then Jared Forsyth suggested I expose functions (the prop getters) to get props to apply to the elements rendered. That bit of inspiration made a big impact on the flexibility and simplicity of this API.
I also took a few ideas from the code in
react-autocomplete and jQuery UI's
Autocomplete.
You can watch me build the first iteration of downshift on YouTube:
You'll find more recordings of me working on downshift on my livestream
YouTube playlist.
You can implement these other solutions using downshift, but if you'd prefer
to use these out of the box solutions, then that's fine too:
If you're developing some React in ReasonML, check out the Downshift bindings for that.
Thanks goes to these people (emoji key):
This project follows the all-contributors specification. Contributions of any kind welcome!
MIT