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Component and store cases for everything in this series, several of which exist because the thing they pin is invisible everywhere else: - `view-lifecycle` and `keyboard-reach` — a document listener count that does not grow across a simulated navigate cycle, and a tab sequence that reaches the sidebar and plays a row without a mouse. - `notifications`, `notification-store`, `confirm-dialog`, `empty-states` — the four levels, the (level, region, key) coalescing window, and loading/failed/empty as three states. - `card-grid-repaint` — fails if `artists-view`'s or `genres-view`'s per-render arrow functions are hoisted to stable fields, which is the audit's own recommendation and takes the cards from 1 highlighted to 0. It exists for no other reason. - `lazy-track-details` — reads the five sources and fails on a returning static import, the same shape as `TestNoDirectRuntimeEmits` and for the same reason: the invariant is about what the code does *not* say. - `now-playing` — a position report that changes nothing must not touch the DOM again, and a track change must. The first fails against the old unconditional `updated()`. - `playlist-virtualization`, `list-render-cost`, `selection`, `icons`, and the store cases for the library-filter race, the never-settling waiter and the per-playlist patch.
88 lines
3.0 KiB
TypeScript
88 lines
3.0 KiB
TypeScript
/**
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* `tracksByFilePath` is a cache keyed on an array's identity, which is
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* only safe because the stores replace the array whenever its contents
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* change. These tests pin both halves of that: the cache is reused for
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* the same array, and a new array gets a new map.
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*
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* The reason it exists is `perf.m6`: five components resolved selected
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* file paths back to tracks with `filePaths.map(fp => tracks.find(…))`,
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* O(selection × total). Measured through the real opener at 50 000
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* tracks, "Select all → Edit tags" blocked the main thread for
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* 3.0–6.3 s; with the map, 68 ms.
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*/
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import { describe, expect, it } from 'vitest';
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import { tracksByFilePath, tracksForPaths } from '@utils/track-index';
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type Track = { FilePath: string; Title: string };
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const track = (n: number): Track => ({
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FilePath: `/music/${n}.mp3`,
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Title: `Track ${n}`,
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});
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// The util is typed against the generated `library.Track`; these
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// fixtures carry only the fields it reads.
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const asTracks = (t: Track[]) => t as unknown as Parameters<
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typeof tracksByFilePath
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>[0];
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describe('tracksByFilePath', () => {
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it('indexes by file path', () => {
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const tracks = asTracks([track(1), track(2), track(3)]);
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const map = tracksByFilePath(tracks);
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expect(map.size).toBe(3);
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expect(map.get('/music/2.mp3')).toBe(tracks[1]);
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expect(map.get('/music/nope.mp3')).toBeUndefined();
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});
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it('reuses the map for the same array', () => {
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const tracks = asTracks([track(1), track(2)]);
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expect(tracksByFilePath(tracks)).toBe(tracksByFilePath(tracks));
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});
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it('builds a fresh map for a replaced array', () => {
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// The store shares unchanged members and replaces the array,
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// so identity is the invalidation signal.
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const first = asTracks([track(1)]);
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const second = asTracks([track(1), track(2)]);
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expect(tracksByFilePath(second)).not.toBe(tracksByFilePath(first));
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expect(tracksByFilePath(second).size).toBe(2);
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});
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it('keeps the first of a duplicated path, as find() did', () => {
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const a = { FilePath: '/music/1.mp3', Title: 'first' };
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const b = { FilePath: '/music/1.mp3', Title: 'second' };
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expect(tracksByFilePath(asTracks([a, b])).get('/music/1.mp3'))
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.toBe(a);
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});
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});
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describe('tracksForPaths', () => {
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it('resolves in the order asked for, not list order', () => {
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const tracks = asTracks([track(1), track(2), track(3)]);
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const got = tracksForPaths(
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tracks,
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['/music/3.mp3', '/music/1.mp3'],
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);
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expect(got.map((t) => t.FilePath))
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.toEqual(['/music/3.mp3', '/music/1.mp3']);
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});
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it('drops paths that are not in the list', () => {
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const tracks = asTracks([track(1)]);
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expect(tracksForPaths(tracks, ['/music/1.mp3', '/gone.mp3']))
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.toHaveLength(1);
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});
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it('is empty for an empty selection', () => {
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expect(tracksForPaths(asTracks([track(1)]), [])).toEqual([]);
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});
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});
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