| 1 | // Run: tsx src/__tests__/scroll-manager.test.tsx |
| 2 | |
| 3 | import { JSDOM } from "jsdom"; |
| 4 | import React, { useEffect } from "react"; |
| 5 | import { act } from "react"; |
| 6 | import { createRoot } from "react-dom/client"; |
| 7 | import { useScrollManager } from "../lib/useScrollManager"; |
| 8 | |
| 9 | type ScrollManagerApi = ReturnType<typeof useScrollManager>; |
| 10 | |
| 11 | let passed = 0; |
| 12 | let failed = 0; |
| 13 | |
| 14 | function ok(value: boolean, label: string) { |
| 15 | if (value) { |
| 16 | process.stdout.write(` PASS ${label}\n`); |
| 17 | passed += 1; |
| 18 | } else { |
| 19 | process.stdout.write(` FAIL ${label}\n`); |
| 20 | failed += 1; |
| 21 | } |
| 22 | } |
| 23 | |
| 24 | function eq(actual: unknown, expected: unknown, label: string) { |
| 25 | if (actual === expected) { |
| 26 | ok(true, label); |
| 27 | } else { |
| 28 | ok(false, `${label}: expected ${JSON.stringify(expected)}, got ${JSON.stringify(actual)}`); |
| 29 | } |
| 30 | } |
| 31 | |
| 32 | function Harness({ onReady }: { onReady: (api: ScrollManagerApi) => void }) { |
| 33 | const manager = useScrollManager(); |
| 34 | useEffect(() => onReady(manager), [manager, onReady]); |
| 35 | return ( |
| 36 | <div |
| 37 | ref={manager.scrollRef} |
| 38 | data-testid="transcript" |
| 39 | onScroll={manager.onScroll} |
| 40 | onWheelCapture={manager.onWheelIntent} |
| 41 | onKeyDownCapture={manager.onKeyScrollIntent} |
| 42 | /> |
| 43 | ); |
| 44 | } |
| 45 | |
| 46 | console.log("\nscroll manager manual intent"); |
| 47 | |
| 48 | const dom = new JSDOM("<!doctype html><html><body><div id=\"root\"></div></body></html>", { |
| 49 | pretendToBeVisual: true, |
| 50 | }); |
| 51 | (globalThis as typeof globalThis & { IS_REACT_ACT_ENVIRONMENT: boolean }).IS_REACT_ACT_ENVIRONMENT = true; |
| 52 | globalThis.window = dom.window as unknown as Window & typeof globalThis; |
| 53 | globalThis.document = dom.window.document; |
| 54 | globalThis.Node = dom.window.Node; |
| 55 | globalThis.HTMLElement = dom.window.HTMLElement; |
| 56 | globalThis.Event = dom.window.Event; |
| 57 | globalThis.WheelEvent = dom.window.WheelEvent; |
| 58 | globalThis.requestAnimationFrame = dom.window.requestAnimationFrame.bind(dom.window); |
| 59 | globalThis.cancelAnimationFrame = dom.window.cancelAnimationFrame.bind(dom.window); |
| 60 | |
| 61 | const rootEl = document.getElementById("root"); |
| 62 | if (!rootEl) throw new Error("missing root"); |
| 63 | const root = createRoot(rootEl); |
| 64 | let api: ScrollManagerApi | null = null; |
| 65 | |
| 66 | await act(async () => { |
| 67 | root.render(<Harness onReady={(next) => { api = next; }} />); |
| 68 | }); |
| 69 | |
| 70 | if (!api) throw new Error("scroll manager did not mount"); |
| 71 | const transcript = document.querySelector<HTMLElement>("[data-testid='transcript']"); |
| 72 | if (!transcript) throw new Error("transcript did not render"); |
| 73 | |
| 74 | let scrollTop = 900; |
| 75 | Object.defineProperty(transcript, "clientHeight", { configurable: true, value: 100 }); |
| 76 | Object.defineProperty(transcript, "scrollHeight", { configurable: true, value: 1000 }); |
| 77 | Object.defineProperty(transcript, "scrollTop", { |
| 78 | configurable: true, |
| 79 | get: () => scrollTop, |
| 80 | set: (value) => { scrollTop = value; }, |
| 81 | }); |
| 82 | |
| 83 | await act(async () => { |
| 84 | api?.onScroll(); |
| 85 | }); |
| 86 | eq(api.stick.current, true, "manager starts pinned when the transcript is at the bottom"); |
| 87 | |
| 88 | await act(async () => { |
| 89 | api?.onWheelIntent({ deltaX: 0, deltaY: 48 } as React.WheelEvent<HTMLElement>); |
| 90 | }); |
| 91 | eq(api.stick.current, true, "wheel-down at the bottom keeps tail-follow enabled"); |
| 92 | |
| 93 | await act(async () => { |
| 94 | const released = api?.onWheelIntent({ deltaX: 0, deltaY: -48 } as React.WheelEvent<HTMLElement>); |
| 95 | eq(released, true, "wheel-up at the bottom releases auto-scroll immediately"); |
| 96 | }); |
| 97 | eq(api.stick.current, false, "manual wheel intent breaks the bottom pin before the native scroll event"); |
| 98 | |
| 99 | if (api.stick.current) { |
| 100 | transcript.scrollTop = transcript.scrollHeight; |
| 101 | } |
| 102 | eq(scrollTop, 900, "a queued streaming auto-scroll would not yank after manual wheel intent"); |
| 103 | |
| 104 | scrollTop = 900; |
| 105 | await act(async () => { |
| 106 | api!.stick.current = true; |
| 107 | api?.onWheelIntent({ deltaX: 40, deltaY: 4 } as React.WheelEvent<HTMLElement>); |
| 108 | }); |
| 109 | eq(api.stick.current, true, "horizontal-dominant wheel gestures do not break vertical tail-follow"); |
| 110 | |
| 111 | Object.defineProperty(transcript, "scrollHeight", { configurable: true, value: 100 }); |
| 112 | scrollTop = 0; |
| 113 | await act(async () => { |
| 114 | api!.stick.current = true; |
| 115 | const released = api?.onWheelIntent({ deltaX: 0, deltaY: -48 } as React.WheelEvent<HTMLElement>); |
| 116 | eq(released, false, "wheel intent is ignored when the transcript is not scrollable"); |
| 117 | }); |
| 118 | eq(api.stick.current, true, "short transcripts stay pinned after ignored wheel intent"); |
| 119 | |
| 120 | Object.defineProperty(transcript, "scrollHeight", { configurable: true, value: 1000 }); |
| 121 | scrollTop = 900; |
| 122 | await act(async () => { |
| 123 | api!.stick.current = true; |
| 124 | const released = api?.onWheelIntent({ deltaX: 0, deltaY: -48, ctrlKey: true } as React.WheelEvent<HTMLElement>); |
| 125 | eq(released, false, "ctrl+wheel (trackpad pinch-zoom) is ignored, not treated as scroll intent"); |
| 126 | }); |
| 127 | eq(api.stick.current, true, "pinch-zoom gesture does not release tail-follow"); |
| 128 | |
| 129 | const editTextarea = document.createElement("textarea"); |
| 130 | await act(async () => { |
| 131 | api!.stick.current = true; |
| 132 | const released = api?.onKeyScrollIntent({ key: "Home", target: editTextarea } as unknown as React.KeyboardEvent<HTMLElement>); |
| 133 | eq(released, false, "Home pressed while editing a message textarea is not treated as scroll intent"); |
| 134 | }); |
| 135 | eq(api.stick.current, true, "editing an earlier message does not release the streaming tail-follow"); |
| 136 | |
| 137 | const plainDiv = document.createElement("div"); |
| 138 | await act(async () => { |
| 139 | api!.stick.current = true; |
| 140 | const released = api?.onKeyScrollIntent({ key: "Home", target: plainDiv } as unknown as React.KeyboardEvent<HTMLElement>); |
| 141 | eq(released, true, "Home pressed on a non-editable target still releases tail-follow"); |
| 142 | }); |
| 143 | eq(api.stick.current, false, "keyboard scroll intent from outside an editable field still breaks the bottom pin"); |
| 144 | |
| 145 | await act(async () => { |
| 146 | root.unmount(); |
| 147 | }); |
| 148 | dom.window.close(); |
| 149 | |
| 150 | console.log(`\n${passed} passed, ${failed} failed`); |
| 151 | if (failed > 0) process.exit(1); |
| 152 |