API Reference > geometry-core > ArraysAndInterfaces > GrowableXYArray > isIndexValid isIndexValid Method Test if index is valid for an xyz (point or vector) within this array isIndexValid(index: number): boolean Parameter Type Description index number xyz index to test. Returns - boolean Defined in core/geometry/src/geometry3d/GrowableXYArray.ts Line 187 Last Updated: 15 June, 2021