ReadOnlyObservableCollection.reduce

API / ReadOnlyObservableCollection<TItem> / reduce method

Aggregates the collection to a single item.

This is a public method.

public reduce(callbackfn: (previousValue: TItem, currentItem: TItem, currentIndex: number, array: readonly TItem[]) => TItem): TItem

Parameters

callbackfn: Function, the callback that aggregates two items at a time.
Parameters:
- previousValue: TItem, the current result value, returned from a previous invocation of the callback.
- currentItem: TItem, the item being processed.
- currentIndex: Number, the index of the item being processed.
- collection: IReadOnlyObservableCollection<TItem>, the collection being iterated.
Returns: TItem
Returns the result of the aggregation between the previousValue and currentItem.

Returns: TItem

Returns a single aggregated item.

See

Array.reduce

Aggregates the collection to a single value.

This is a public method.

public reduce<TResult>(callbackfn: (previousValue: TResult, currentItem: TItem, currentIndex: number, array: readonly TItem[]) => TResult, initialValue: TResult): TResult

Template Parameters

TResult: the type of value to aggregate the collection to.

Parameters

callbackfn: Function, the callback that aggregates one item and the previous value at a time.
Parameters:
- previousValue: TResult, the current result value, returned from a previous invocation of the callback.
- currentItem: TItem, the item being processed.
- currentIndex: Number, the index of the item being processed.
- collection: IReadOnlyObservableCollection<TItem>, the collection being iterated.
Returns: TResult
Returns the result of the aggregation between the previousValue and currentItem.
initialValue: TResult, the initial value when aggregating the collection.