diff --git a/packages/shared/src/stroke.ts b/packages/shared/src/stroke.ts
index f850366..df20963 100644
--- a/packages/shared/src/stroke.ts
+++ b/packages/shared/src/stroke.ts
@@ -1,9 +1,18 @@
-export type TecackDataset = [TargetChar, TargetCharStrokeLength, Array<TecackStroke>];
+/**
+ * The TecackDataset.
+ *
+ * @example ["字", 6, [..]]
+ */
+export type TecackDataset = [TargetChar, TargetCharStrokeLength, TecackStrokes];
 
 export type TargetChar = string;
 
 export type TargetCharStrokeLength = number;
 
+/** Stroke information for any single character. */
+export type TecackStrokes = Array<TecackStroke>;
+
+/** Information on a single stroke of any single character. */
 export type TecackStroke = Array<Position>;
 
 export type Position = [X, Y];