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SectionList

A performant interface for rendering sectioned lists, supporting the most handy features:

• Fully cross-platform.
• Configurable viewability callbacks.
• List header support.
• List footer support.
• Item separator support.
• Section header support.
• Section separator support.
• Heterogeneous data and item rendering support.
• Pull to Refresh.
• Scroll loading.

If you don't need section support and want a simpler interface, use <FlatList>.

Simple Examples:

<SectionList
  renderItem={({item}) => <ListItem title={item} />}
  renderSectionHeader={({section}) => <Header title={section.title} />}
  sections={[ // homogeneous rendering between sections
    {data: [...], title: ...},
    {data: [...], title: ...},
    {data: [...], title: ...},
  ]}
/>

<SectionList
  sections={[ // heterogeneous rendering between sections
    {data: [...], renderItem: ...},
    {data: [...], renderItem: ...},
    {data: [...], renderItem: ...},
  ]}
/>

This is a convenience wrapper around <VirtualizedList>, and thus inherits its props (as well as those of <ScrollView> that aren't explicitly listed here, along with the following caveats:

• Internal state is not preserved when content scrolls out of the render window. Make sure all your data is captured in the item data or external stores like Flux, Redux, or Relay.
• This is a PureComponent which means that it will not re-render if props remain shallow- equal. Make sure that everything your renderItem function depends on is passed as a prop (e.g. extraData) that is not === after updates, otherwise your UI may not update on changes. This includes the data prop and parent component state.
• In order to constrain memory and enable smooth scrolling, content is rendered asynchronously offscreen. This means it's possible to scroll faster than the fill rate and momentarily see blank content. This is a tradeoff that can be adjusted to suit the needs of each application, and we are working on improving it behind the scenes.
• By default, the list looks for a key prop on each item and uses that for the React key. Alternatively, you can provide a custom keyExtractor prop.

Props

• ScrollView props...

Required props:

• sections

Optional props:

• initialNumToRender
• keyExtractor
• renderItem
• onEndReached
• extraData
• ItemSeparatorComponent
• inverted
• ListFooterComponent
• legacyImplementation
• ListEmptyComponent
• onEndReachedThreshold
• onRefresh
• onViewableItemsChanged
• refreshing
• removeClippedSubviews
• ListHeaderComponent
• renderSectionFooter
• renderSectionHeader
• SectionSeparatorComponent
• stickySectionHeadersEnabled

Methods

• scrollToLocation
• recordInteraction
• flashScrollIndicators

Type Definitions

• Section

---

Reference

Props

sections

The actual data to render, akin to the data prop in FlatList.

Type	Required
array of Sections	Yes

---

initialNumToRender

How many items to render in the initial batch. This should be enough to fill the screen but not much more. Note these items will never be unmounted as part of the windowed rendering in order to improve perceived performance of scroll-to-top actions.

Type	Required
number	Yes

---

keyExtractor

Used to extract a unique key for a given item at the specified index. Key is used for caching and as the react key to track item re-ordering. The default extractor checks item.key, then falls back to using the index, like react does. Note that this sets keys for each item, but each overall section still needs its own key.

Type	Required
(item: Item, index: number) => string	Yes

---

renderItem

Default renderer for every item in every section. Can be over-ridden on a per-section basis. Should return a React element.

Type	Required
function	Yes

The render function will be passed an object with the following keys:

• 'item' (object) - the item object as specified in this section's data key
• 'index' (number) - Item's index within the section.
• 'section' (object) - The full section object as specified in sections.
• 'separators' (object) - An object with the following keys:
  • 'highlight' (function) - () => void
  • 'unhighlight' (function) - () => void
  • 'updateProps' (function) - (select, newProps) => void
    • 'select' (enum) - possible values are 'leading', 'trailing'
    • 'newProps' (object)

---

onEndReached

Called once when the scroll position gets within onEndReachedThreshold of the rendered content.

Type	Required
[(info: {distanceFromEnd: number}) => void]	No

---

extraData

A marker property for telling the list to re-render (since it implements PureComponent). If any of your renderItem, Header, Footer, etc. functions depend on anything outside of the data prop, stick it here and treat it immutably.

Type	Required
any	No

---

ItemSeparatorComponent

Rendered in between each item, but not at the top or bottom. By default, highlighted, section, and [leading/trailing][Item/Separator] props are provided. renderItem provides separators.highlight/unhighlight which will update the highlighted prop, but you can also add custom props with separators.updateProps.

Type	Required
[component, function, element]	No

---

inverted

Reverses the direction of scroll. Uses scale transforms of -1.

Type	Required
[boolean]	No

---

ListFooterComponent

Rendered at the very end of the list. Can be a React Component Class, a render function, or a rendered element.

Type	Required
[component, function, element]	No

---

legacyImplementation

Type	Required
[boolean]	No

---

ListEmptyComponent

Rendered when the list is empty. Can be a React Component Class, a render function, or a rendered element.

Type	Required
[component, function, element]	No

---

onEndReachedThreshold

How far from the end (in units of visible length of the list) the bottom edge of the list must be from the end of the content to trigger the onEndReached callback. Thus a value of 0.5 will trigger onEndReached when the end of the content is within half the visible length of the list.

Type	Required
[number]	No

---

onRefresh

If provided, a standard RefreshControl will be added for "Pull to Refresh" functionality. Make sure to also set the refreshing prop correctly.

Type	Required
[() => void]	No

---

onViewableItemsChanged

Called when the viewability of rows changes, as defined by the viewabilityConfig prop.

Type	Required
function	No

The function will be passed an object with the following keys:

• 'viewableItems' (array of ViewTokens)
• 'changed' (array of ViewTokens)

The ViewToken type is exported by ViewabilityHelper.js:

Name	Type	Required
item	any	Yes
key	string	Yes
index	number	No
isViewable	boolean	Yes
section	any	No

---

refreshing

Set this true while waiting for new data from a refresh.

Type	Required
[boolean]	No

---

removeClippedSubviews

Note: may have bugs (missing content) in some circumstances - use at your own risk.

This may improve scroll performance for large lists.

Type	Required
boolean	No

---

ListHeaderComponent

Rendered at the very beginning of the list. Can be a React Component Class, a render function, or a rendered element.

Type	Required
component, function, element	No

---

renderSectionFooter

Rendered at the bottom of each section.

Type	Required
[(info: {section: SectionT}) => ?React.Element]	No

---

renderSectionHeader

Rendered at the top of each section. These stick to the top of the ScrollView by default on iOS. See stickySectionHeadersEnabled.

Type	Required
[(info: {section: SectionT}) => ?React.Element]	No

---

SectionSeparatorComponent

Rendered at the top and bottom of each section (note this is different from ItemSeparatorComponent which is only rendered between items). These are intended to separate sections from the headers above and below and typically have the same highlight response as ItemSeparatorComponent. Also receives highlighted, [leading/trailing][Item/Separator], and any custom props from separators.updateProps.

Type	Required
[ReactClass]	No

---

stickySectionHeadersEnabled

Makes section headers stick to the top of the screen until the next one pushes it off. Only enabled by default on iOS because that is the platform standard there.

Type	Required
boolean	No

Methods

scrollToLocation()

scrollToLocation(params);

Scrolls to the item at the specified sectionIndex and itemIndex (within the section) positioned in the viewable area such that viewPosition 0 places it at the top (and may be covered by a sticky header), 1 at the bottom, and 0.5 centered in the middle.

Note: Cannot scroll to locations outside the render window without specifyingthe getItemLayout prop.

Parameters:

Name	Type	Required	Description
params	object	Yes	See below.

Valid params keys are:

• 'animated' (boolean) - Whether the list should do an animation while scrolling. Defaults to true.
• 'itemIndex' (number) - Index within section for the item to scroll to. Required.
• 'sectionIndex' (number) - Index for section that contains the item to scroll to. Required.
• 'viewOffset' (number) - A fixed number of pixels to offset the final target position, e.g. to compensate for sticky headers.
• 'viewPosition' (number) - A value of 0 places the item specified by index at the top, 1 at the bottom, and 0.5 centered in the middle.

---

recordInteraction()

recordInteraction();

Tells the list an interaction has occured, which should trigger viewability calculations, e.g. if waitForInteractions is true and the user has not scrolled. This is typically called by taps on items or by navigation actions.

---

flashScrollIndicators()

flashScrollIndicators();

Displays the scroll indicators momentarily.

Type Definitions

Section

An object that identifies the data to be rendered for a given section.

Type
any

Properties:

Name	Type	Description
data	array	The data for rendering items in this section. Array of objects, much like FlatList's data prop.
[key]	string	Optional key to keep track of section re-ordering. If you don't plan on re-ordering sections,
the array index will be used by default.
[renderItem]	function	Optionally define an arbitrary item renderer for this section, overriding the default renderItem for the list.
[ItemSeparatorComponent]	component, function, element	Optionally define an arbitrary item separator for this section, overriding the default ItemSeparatorComponent for the list.
[keyExtractor]	function	Optionally define an arbitrary key extractor for this section, overriding the default keyExtractor.