diff --git a/src/Shape.ts b/src/Shape.ts
index 879f08a4..5406bec6 100644
--- a/src/Shape.ts
+++ b/src/Shape.ts
@@ -21,6 +21,9 @@ export type ShapeConfigHandler<TTarget> = {
   bivarianceHack(ctx: Context, shape: TTarget): void;
 }['bivarianceHack'];
 
+export type LineJoin = 'round' | 'bevel' | 'miter';
+export type LineCap = 'butt' | 'round' | 'square';
+
 export interface ShapeConfig extends NodeConfig {
   fill?: string;
   fillPatternImage?: HTMLImageElement;
@@ -58,8 +61,8 @@ export interface ShapeConfig extends NodeConfig {
   strokeScaleEnabled?: boolean;
   strokeHitEnabled?: boolean;
   strokeEnabled?: boolean;
-  lineJoin?: string;
-  lineCap?: string;
+  lineJoin?: LineJoin;
+  lineCap?: LineCap;
   sceneFunc?: (con: Context, shape: Shape) => void;
   hitFunc?: (con: Context, shape: Shape) => void;
   shadowColor?: string;
@@ -789,8 +792,8 @@ export class Shape<Config extends ShapeConfig = ShapeConfig> extends Node<
   fillPatternY: GetSet<number, this>;
   fillPriority: GetSet<string, this>;
   hitFunc: GetSet<ShapeConfigHandler<this>, this>;
-  lineCap: GetSet<string, this>;
-  lineJoin: GetSet<string, this>;
+  lineCap: GetSet<LineCap, this>;
+  lineJoin: GetSet<LineJoin, this>;
   perfectDrawEnabled: GetSet<boolean, this>;
   sceneFunc: GetSet<ShapeConfigHandler<this>, this>;
   shadowColor: GetSet<string, this>;