Folding

kotlin

data class FoldRegion(
    val startLine: Int,
    val endLine: Int,
    val collapsed: Boolean = false,
)

Lines are 0-based inclusive.

kotlin

fun setFoldRegions(regions: List<FoldRegion>)
fun toggleFold(line: Int)
fun foldAt(line: Int)
fun unfoldAt(line: Int)
fun foldAll()
fun unfoldAll()
fun isLineVisible(line: Int): Boolean

isLineVisible is true before ready (no folds yet).

FoldToggleEvent is published when the user clicks a fold arrow. Arrow visibility follows EditorSettings.foldArrowMode.

You can also supply fold regions from a DecorationProvider (foldRegions / foldRegionsMode).

Folding ​

Folding