sub
Returns a Flow that emits a sublist view of this reactive list between the specified fromIndex (inclusive) and toIndex (exclusive).
This function observes the reactive list and emits a new sublist snapshot whenever the original list's content changes in a way that affects the sublist. It prevents emissions of identical subsequent sublists.
Behavior Modes
Strict Mode (default: strict = true)
Returns an empty list if any index is out of bounds or invalid
Validates that
0 <= fromIndex <= toIndex <= list.size
Lenient Mode (strict = false)
Automatically coerces indices to valid ranges using coerceIn
Useful when you want to observe "as much as possible" of a range
Example:
val numbers = reactiveListOf(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
// Observe elements from index 2 to 5 (exclusive) in strict mode
numbers.subListAsFlow(2, 5, strict = true).collect { sublist ->
println("Strict sublist [2,5): $sublist")
}
// Observe the same range in lenient mode
numbers.subListAsFlow(2, 5, strict = false).collect { sublist ->
println("Lenient sublist [2,5): $sublist")
}
// Modify the list
delay(1000)
numbers.removeAt(0)
delay(1000)
numbers.retainAll(setOf(2, 3, 4))
// Flow emissions:
// Lenient sublist [2,5): [2, 3, 4]
// Strict sublist [2,5): [2, 3, 4]
// Strict sublist [2,5): [3, 4, 5]
// Lenient sublist [2,5): [3, 4, 5]
// Strict sublist [2,5): []
// Lenient sublist [2,5): [4]Return
A Flow that emits the specified sublist when the source list changes.
Parameters
The type of elements in the list.
The starting index of the sublist (inclusive).
The ending index of the sublist (exclusive).
If true (default), an empty list is returned for any invalid indices. This approach avoids exceptions for invalid ranges. If false (lenient mode), indices are safely coerced to the valid range.