@lewisl9029/downshift
v0.0.4
Published
A set of primitives to build simple, flexible, WAI-ARIA compliant React autocomplete components
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See the intro blog post and Episode 79 of the Full Stack Radio podcast
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The problem
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 solution
This library provides its users two main sets of solutions: the Downshift
component and a set of hooks. The component is still the main part of the
library, providing autocomplete/combobox logic as a render prop. The hooks are
newer and are going to be the way forward to provide accessibility logic to
widgets. Right now we support useSelect
for <select>
components and
useCombobox
for combobox/autocomplete.
Since useCombobox
and <Downshift />
aim to provide accessibility to the same
kind of widget, we suggest trying the new useCombobox
and if you feel that
<Downshift />
still covers your use case better then use that instead. Both of
them are actively maintained but we are cool kids from the future and prefer to
share React
logic via hooks.
The README
on this page is only for the component while each hook has its own
README
file, check below. But they are similar in many concepts so you can
always switch between them in order to find information.
Downshift component
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][use-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.
The Hooks API
In the effort to provide out of the box solutions for each dropdown variation, a
set of React Hooks are being added as part of Downshift. Each hook will handle a
specific dropdown variation and be named accordingly: useSelect
,
useCombobox
, useMultipleSelection
etc.
You can check the progress in the [hooks page][hooks-readme] and contribute! If
you want to create a custom <select>
or combobox autocomplete
dropdown and
want it to be functional and accessible, jump directly to the already
implemented [useSelect][useselect-readme] and [useCombobox][combobox-readme].
For more examples of how to use the hooks check out our
docsite!
Bundle size concerns
Adding the hooks into this repo increased the bundle size considerably
throughout its existence. However, since we create the bundle with Rollup
and
export both <Downshift>
and the hooks as modules, you should be able to have
the library treeshaked (pruned) and given only the code you need. Since version
3.4.8
BundlePhobia marked Downshift
as both tree-shakeable
and
side-effect free
[here][bundle-phobia-link].
Table of Contents
- Installation
- Usage
- Basic Props
- Advanced Props
- initialSelectedItem
- initialInputValue
- initialHighlightedIndex
- initialIsOpen
- defaultHighlightedIndex
- defaultIsOpen
- selectedItemChanged
- getA11yStatusMessage
- onSelect
- onStateChange
- onInputValueChange
- itemCount
- highlightedIndex
- inputValue
- isOpen
- selectedItem
- id
- inputId
- labelId
- menuId
- getItemId
- environment
- onOuterClick
- scrollIntoView
- 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
Installation
This module is distributed via [npm][npm] which is bundled with [node][node] and
should be installed as one of your project's dependencies
:
npm install --save downshift
This package also depends on
react
. Please make sure you have it installed as well.
Note also this library supports
preact
out of the box. If you are usingpreact
then use the corresponding module in thepreact/dist
folder. You can evenimport Downshift from 'downshift/preact'
👍
Usage
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(selection ? `You selected ${selection.value}` : 'Selection Cleared')
}
itemToString={item => (item ? item.value : '')}
>
{({
getInputProps,
getItemProps,
getLabelProps,
getMenuProps,
isOpen,
inputValue,
highlightedIndex,
selectedItem,
getRootProps,
}) => (
<div>
<label {...getLabelProps()}>Enter a fruit</label>
<div
style={{display: 'inline-block'}}
{...getRootProps({}, {suppressRefError: true})}
>
<input {...getInputProps()} />
</div>
<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'),
)
The previous example without getRootProps
is
here.
Warning: The example without
getRootProps
is not fully accessible with screen readers as it's not possible to achieve a correct HTML structure for the combobox. Examples on how to useDownshift
component with and withoutgetRootProps
are on the docsite.
<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!"][use-a-render-prop]!
<Downshift>{downshift => <div>/* your JSX here! */</div>}</Downshift>
.
Basic Props
This is the list of props that you should probably know about. There are some advanced props below as well.
children
function({})
| required
This is called with an object. Read more about the properties of this object in the section "Children Function".
itemToString
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
).
onChange
function(selectedItem: any, stateAndHelpers: object)
| optional, no useful default
Called when the selected item changes, either by the user selecting an item or
the user clearing the selection. Called with the item that was selected or
null
and the new state of downshift
. (see onStateChange
for more info on
stateAndHelpers
).
selectedItem
: The item that was just selected.null
if the selection was cleared.stateAndHelpers
: This is the same thing yourchildren
function is called with (see Children Function)
stateReducer
function(state: object, changes: object)
| optional
🚨 This is a really handy power feature 🚨
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 atype
property which you can learn more about in thestateChangeTypes
section.
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
}
}
NOTE: This is only called when state actually changes. You should not attempt to use this to handle events. If you wish to handle events, put your event handlers directly on the elements (make sure to use the prop getters though! For example:
<input onBlur={handleBlur} />
should be<input {...getInputProps({onBlur: handleBlur})} />
). Also, your reducer function should be "pure." This means it should do nothing other than return the state changes you want to have happen.
Advanced Props
initialSelectedItem
any
| defaults tonull
Pass an item or an array of items that should be selected when downshift is initialized.
initialInputValue
string
| defaults to''
This is the initial input value when downshift is initialized.
initialHighlightedIndex
number
/null
| defaults todefaultHighlightedIndex
This is the initial value to set the highlighted index to when downshift is initialized.
initialIsOpen
boolean
| defaults todefaultIsOpen
This is the initial isOpen
value when downshift is initialized.
defaultHighlightedIndex
number
/null
| defaults tonull
This is the value to set the highlightedIndex
to anytime downshift is reset,
when the selection is cleared, when an item is selected or when the inputValue
is changed.
defaultIsOpen
boolean
| defaults tofalse
This is the value to set the isOpen
to anytime downshift is reset, when the
the selection is cleared, or when an item is selected.
selectedItemChanged
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.
getA11yStatusMessage
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 |
onSelect
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 yourchildren
function is called with (see Children Function)
onStateChange
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 atype
property which you can learn more about in thestateChangeTypes
section.stateAndHelpers
: This is the exact same thing yourchildren
function 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')
.
NOTE: This is only called when state actually changes. You should not attempt to use this to handle events. If you wish to handle events, put your event handlers directly on the elements (make sure to use the prop getters though! For example:
<input onBlur={handleBlur} />
should be<input {...getInputProps({onBlur: handleBlur})} />
).
onInputValueChange
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 yourchildren
function is called with (see Children Function)
itemCount
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
).
highlightedIndex
number
| control prop (read more about this in the Control Props section)
The index that should be highlighted
inputValue
string
| control prop (read more about this in the Control Props section)
The value the input should have
isOpen
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).
selectedItem
any
/Array(any)
| control prop (read more about this in the Control Props section)
The currently selected item.
id
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.
inputId
string
| defaults to a generated ID
Used for aria
attributes and the id
prop of the element (input
) you use
getInputProps
with.
labelId
string
| defaults to a generated ID
Used for aria
attributes and the id
prop of the element (label
) you use
getLabelProps
with.
menuId
string
| defaults to a generated ID
Used for aria
attributes and the id
prop of the element (ul
) you use
getMenuProps
with.
getItemId
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.
environment
window
| defaults towindow
This prop is only useful if you're rendering downshift within a different
window
context from where your JavaScript is running; for example, an iframe
or a shadow-root. If the given context is lacking document
and/or
add|removeEventListener
on its prototype (as is the case for a shadow-root)
then you will need to pass in a custom object that is able to provide
access to these properties
for downshift.
onOuterClick
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
.
scrollIntoView
function(node: HTMLElement, menuNode: HTMLElement)
| defaults to internal implementation
This allows you to customize how the scrolling works when the highlighted index
changes. It receives the node to be scrolled to and the root node (the root node
you render in downshift). Internally we use
compute-scroll-into-view
so if you use that package then you wont be adding any additional bytes to your
bundle :)
stateChangeTypes
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.
The list of all possible values this type
property can take is defined in
this file
and is as follows:
Downshift.stateChangeTypes.unknown
Downshift.stateChangeTypes.mouseUp
Downshift.stateChangeTypes.itemMouseEnter
Downshift.stateChangeTypes.keyDownArrowUp
Downshift.stateChangeTypes.keyDownArrowDown
Downshift.stateChangeTypes.keyDownEscape
Downshift.stateChangeTypes.keyDownEnter
Downshift.stateChangeTypes.clickItem
Downshift.stateChangeTypes.blurInput
Downshift.stateChangeTypes.changeInput
Downshift.stateChangeTypes.keyDownSpaceButton
Downshift.stateChangeTypes.clickButton
Downshift.stateChangeTypes.blurButton
Downshift.stateChangeTypes.controlledPropUpdatedSelectedItem
Downshift.stateChangeTypes.touchEnd
See stateReducer
for a concrete example on how to use the
type
property.
Control Props
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
Children Function
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:
prop getters
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. |
getRootProps
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).
There are no required properties for this method.
Optional 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} />
. It defaults toref
.
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.
getInputProps
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 fromgetInputProps
and adisabled
prop will be returned (effectively disabling the input).
getLabelProps
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.
getMenuProps
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:
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:getMenuProps({refKey: 'innerRef'})
and your composite component would forward like:<ul ref={props.innerRef} />
. However, if you are just rendering a primitive component like<div>
, there is no need to specify this property. It defaults toref
.Please keep in mind that menus, for accessibility purposes, should always be rendered, regardless of whether you hide it or not. Otherwise,
getMenuProps
may throw error if you unmount and remount the menu.aria-label
: By default the menu will add anaria-labelledby
that refers to the<label>
rendered withgetLabelProps
. However, if you providearia-label
to give a more specific label that describes the options available, thenaria-labelledby
will not be provided and screen readers can use youraria-label
instead.
In some cases, you might want to completely bypass the refKey
check. Then you
can provide the object {suppressRefError : true}
as the second argument to
getMenuProps
. Please use it with extreme care and only if you are absolutely
sure that the ref is correctly forwarded otherwise Downshift
will unexpectedly
fail.
<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
isOpen
state.
getItemProps
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.
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 howdownshift
keeps track of your item when updating thehighlightedIndex
as the user keys around. By default,downshift
will assume theindex
is 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 aboutindex
when 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.
getToggleButtonProps
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-label
prop 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'),
})}
/>
)
actions
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
). |
otherStateToSet
refers to an object to set other internal state. It is recommended to avoid abusing this, but is available if you need it.
state
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 |
props
As a convenience, the id
and itemToString
props which you pass to
<Downshift />
are available here as well.
Event Handlers
Downshift has a few events for which it provides implicit handlers. Several of
these handlers call event.preventDefault()
. Their additional functionality is
described below.
default handlers
ArrowDown
: if menu is closed, opens it and moves the highlighted index todefaultHighlightedIndex + 1
, ifdefaultHighlightedIndex
is provided, or to the top-most item, if not. If menu is open, it moves the highlighted index down by 1. If the shift key is held when this event fires, the highlighted index will jump down 5 indices instead of 1. NOTE: if the current highlighted index is within the bottom 5 indices, the top-most index will be highlighted.)ArrowUp
: if menu is closed, opens it and moves the highlighted index todefaultHighlightedIndex - 1
, ifdefaultHighlightedIndex
is provided, or to the bottom-most item, if not. If menu is open, moves the highlighted index up by 1. If the shift key is held when this event fires, the highlighted index will jump up 5 indices instead of 1. NOTE: if the current highlighted index is within the top 5 indices, the bottom-most index will be highlighted.)Home
: if menu is closed, it will not add any other behavior. If menu is open, the top-most index will get highlighted.End
: if menu is closed, it will not add any other behavior. If menu is open, the bottom-most index will get highlighted.Enter
: if the menu is open, selects 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 clear downshift's state. This means thathighlightedIndex
will be set to thedefaultHighlightedIndex
, theinputValue
will be set to empty string,selectedItem
will be set tonull
, and theisOpen
state will be set to thedefaultIsOpen
.
customizing handlers
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>
)
Utilities
resetIdCounter
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(...);
React Native
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.
Gotchas
- Your root view will need to either pass a ref to
getRootProps
or callgetRootProps
with{ 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 thekeyboardShouldPersistTaps
prop to ensure that your text input stays focus, while allowing for taps on the touchables rendered for your items.
Advanced React Component Patterns course
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
🚨 We're in the process of moving all examples to the downshift-examples repo (which you can open, interact with, and contribute back to live on codesandbox)
Ordered Examples:
If you're just learning downshift, review these in order:
- basic autocomplete - very bare bones, not styled at all. Good place to start.
- styled autocomplete - more complete autocomplete solution using emotion for styling and match-sorter for filtering the items.
- typeahead -
Shows how to control the
selectedItem
so the selected item can be one of your items or whatever the user types. - multi-select - Shows how to create a MultiDownshift component that allows for an array of selectedItems for multiple selection using a state reducer
Other Examples:
Check out these examples of more advanced use/edge cases:
- dropdown with select by key - An example of using the render prop pattern to utilize a reusable component to provide the downshift dropdown component with the functionality of being able to highlight a selection item that starts with the key pressed.
- using actions - An example of using one of downshift's actions as an event handler.
- gmail's composition recipients field - An example of a highly complex autocomplete component featuring asynchronously loading items, multiple selection, and windowing (with react-virtualized)
- Downshift HOC and Compound Components -
An example of how to implementat compound components with
React.createContext
and a downshift higher order component. This is generally not recommended because the render prop API exported by downshift is generally good enough for everyone, but there's nothing technically wrong with doing something like this.
Old Examples exist on [codesandbox.io][examples]:
🚨 This is a great contribution opportunity! These are examples that have not yet been migrated to downshift-examples. You're more than welcome to make PRs to the examples repository to move these examples over there. Watch this to learn how to contribute completely in the browser
- Integration with Apollo
- Integration with Redux
- Integration with
react-instantsearch
from 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 aboutgenie
here) - 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
withDownshift
higher 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
FAQ
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>
)
Inspiration
I was heavily inspired by [Ryan Florence][ryan]. Watch his (free) lesson about ["Compound Components"][compound-components-lecture]. Initially downshift was a group of compound components using context to communicate. But then [Jared Forsyth][jared] 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
][react-autocomplete] and [jQuery UI's
Autocomplete][jquery-complete].
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][yt-playlist].
Other Solutions
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:
Bindings for ReasonML
If you're developing some React in ReasonML, check out the
Downshift
bindings for
that.
Contributors
Thanks goes to these people ([emoji key][emojis]):