refactor(web): extract timeline touch helpers

2026-04-01 09:48:04 +02:00
parent 167eec31de
commit 3abb3bc865
4 changed files with 151 additions and 30 deletions
@@ -0,0 +1,75 @@
+import { describe, expect, it } from "vitest";
+import { getTouchPoint, resolveTouchDragDecision } from "./timelineTouch.js";
+
+describe("timelineTouch", () => {
+  it("falls back from active touches to changedTouches and then zeroes", () => {
+    expect(
+      getTouchPoint({
+        touches: [{ clientX: 12, clientY: 18 }],
+        changedTouches: [{ clientX: 40, clientY: 55 }],
+      }),
+    ).toEqual({ clientX: 12, clientY: 18 });
+
+    expect(
+      getTouchPoint({
+        touches: [],
+        changedTouches: [{ clientX: 40, clientY: 55 }],
+      }),
+    ).toEqual({ clientX: 40, clientY: 55 });
+
+    expect(
+      getTouchPoint({
+        touches: [],
+        changedTouches: [],
+      }),
+    ).toEqual({ clientX: 0, clientY: 0 });
+  });
+
+  it("stays undecided and ignores tiny movements below the threshold", () => {
+    expect(
+      resolveTouchDragDecision(
+        { x: 100, y: 100, decided: false },
+        { clientX: 106, clientY: 107 },
+      ),
+    ).toEqual({
+      nextState: { x: 100, y: 100, decided: false },
+      shouldHandleDrag: false,
+    });
+  });
+
+  it("lets vertical scrolling win once movement is mostly vertical", () => {
+    expect(
+      resolveTouchDragDecision(
+        { x: 100, y: 100, decided: false },
+        { clientX: 106, clientY: 118 },
+      ),
+    ).toEqual({
+      nextState: { x: 100, y: 100, decided: true },
+      shouldHandleDrag: false,
+    });
+  });
+
+  it("switches to drag handling once horizontal movement wins", () => {
+    expect(
+      resolveTouchDragDecision(
+        { x: 100, y: 100, decided: false },
+        { clientX: 118, clientY: 106 },
+      ),
+    ).toEqual({
+      nextState: { x: 100, y: 100, decided: true },
+      shouldHandleDrag: true,
+    });
+  });
+
+  it("keeps handling drag after the decision was already made", () => {
+    expect(
+      resolveTouchDragDecision(
+        { x: 100, y: 100, decided: true },
+        { clientX: 101, clientY: 140 },
+      ),
+    ).toEqual({
+      nextState: { x: 100, y: 100, decided: true },
+      shouldHandleDrag: true,
+    });
+  });
+});