Scroll Location

AutoscrollToBottom

AutoscrollToBottom<Data, Context> = ItemLocationCallback<Data, Context> | NonNullable<ScrollToOptions["behavior"]> | boolean

Specifies the list behavior to perform when the list data changes.

Type Parameters

Type Parameter	Default type	Description
Data	unknown	The type of the data items in the list.
Context	unknown	The type of the context passed to the list.

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ItemLocation

ItemLocation = number | ItemLocationWithAlign

A location in the list to scroll to. Passing a number scrolls instantly to the item at the specified index aligned to the top. See ItemLocationWithAlign for more advanced options.

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ItemLocationCallback

ItemLocationCallback<Data, Context> = (params) => ScrollBehavior | boolean | ItemLocation

A callback function that determines the scroll behavior when data changes.

Type Parameters

Type Parameter	Default type	Description
Data	unknown	The type of the data items in the list.
Context	unknown	The type of the context passed to the list.

Parameters

Parameter	Type
params	ItemLocationCallbackParams<Data, Context>

Returns

ScrollBehavior | boolean | ItemLocation

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ItemLocationCallbackParams

The parameters passed to the ItemLocationCallback function.

Type Parameters

Type Parameter	Default type	Description
Data	unknown	The type of the data items in the list.
Context	unknown	The type of the context passed to the list.

Properties

atBottom

boolean

Whether the list is at the bottom before the data change.

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context

Context

The context passed to the list.

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data

Data[]

The new data that will be appended to the list.

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scrollInProgress

boolean

Indicates whether the list is currently scrolling. If you receive fast updates and use 'smooth' scrolling, there’s a chance that the list will be in the middle of a scroll when new data arrives.

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scrollLocation

ListScrollLocation

The location of the list before the data change. See ListScrollLocation for the details of the parameter received.

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ItemLocationWithAlign

Specifies a location in the list to scroll to.

Properties

align?: "start" | "center" | "end" | "start-no-overflow"

How to align the item in the viewport.

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behavior?: ScrollBehavior

Set 'smooth' to have an animated transition to the specified location.

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done()?

optional done: () => void

A callback that’s invoked when the scroll is complete.

Returns

void

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index

number | "LAST"

The index of the item to scroll to. Use 'LAST' to scroll to the last item.

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offset?: number

Use the offset for additional adjustment of the position - can be a positive or negative number.

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ScrollModifier

ScrollModifier = null | undefined | { location: ItemLocation; purgeItemSizes?: boolean; type: "item-location"; } | { autoScroll: AutoscrollToBottom; type: "auto-scroll-to-bottom"; } | { behavior: ScrollBehavior | { location: () => ItemLocation | null | undefined; }; type: "items-change"; } | ScrollModifierOptionValue

Describes the scroll modification to perform when the data of the list is updated. See the scroll modifier documentation section for examples of how to use this type.

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ScrollModifierOption

const ScrollModifierOption: object

Predefined scroll modifier options for common data operations.

Type Declaration

prepend

"prepend"

removeFromEnd

"remove-from-end"

removeFromStart

"remove-from-start"

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ScrollModifierOptionType

ScrollModifierOptionType = typeof ScrollModifierOption

The type of the ScrollModifierOption constant.

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ScrollModifierOptionValue

ScrollModifierOptionValue = ScrollModifierOptionType[keyof ScrollModifierOptionType]

The possible values of the ScrollModifierOption constant.

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ShortSizeAlign

ShortSizeAlign = "top" | "bottom" | "bottom-smooth"

Specifies the alignment of the items when the content of the list is smaller than the viewport height.

• 'top' (default), the items will be aligned to the top
• 'bottom', the items will be aligned to the bottom.
• 'bottom-smooth', the items will be aligned to the bottom and the scroll will be animated.