1# Interfaces cannot extend classes 2 3Rule ``arkts-extends-only-class`` 4 5**Severity: error** 6 7ArkTS does not support interfaces that extend classes. Interfaces can extend 8only interfaces. 9 10 11## TypeScript 12 13 14``` 15 16 class Control { 17 state: number = 0 18 } 19 20 interface SelectableControl extends Control { 21 select(): void 22 } 23 24``` 25 26## ArkTS 27 28 29``` 30 31 interface Control { 32 state: number 33 } 34 35 interface SelectableControl extends Control { 36 select(): void 37 } 38 39``` 40 41 42