LeonSGP43
109 lines
2.7 KiB
TypeScript
109 lines
2.7 KiB
TypeScript
import { describe, expect, it } from 'vitest'
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import {
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getScrollbarSnapshot,
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getViewportSnapshot,
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scrollbarSnapshotKey,
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viewportSnapshotKey
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} from '../lib/viewportStore.js'
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describe('viewportStore', () => {
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it('normalizes absent scroll handles', () => {
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expect(getViewportSnapshot(null)).toEqual({
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atBottom: true,
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bottom: 0,
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pending: 0,
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scrollHeight: 0,
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top: 0,
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viewportHeight: 0
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})
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})
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it('includes pending scroll delta in snapshot math and keying', () => {
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const handle = {
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getPendingDelta: () => 3,
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getScrollHeight: () => 40,
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getScrollTop: () => 10,
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getViewportHeight: () => 5,
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isSticky: () => false
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}
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const snap = getViewportSnapshot(handle as any)
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expect(snap).toMatchObject({
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atBottom: false,
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bottom: 18,
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pending: 3,
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scrollHeight: 40,
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top: 13,
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viewportHeight: 5
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})
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expect(viewportSnapshotKey(snap)).toBe('0:16:5:40:3')
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})
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it('uses fresh scroll height to clear stale non-bottom state', () => {
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const handle = {
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getFreshScrollHeight: () => 20,
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getPendingDelta: () => 0,
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getScrollHeight: () => 40,
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getScrollTop: () => 15,
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getViewportHeight: () => 5,
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isSticky: () => false
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}
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const snap = getViewportSnapshot(handle as any)
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expect(snap.atBottom).toBe(true)
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expect(snap.scrollHeight).toBe(20)
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})
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it('keeps scrollbar position tied to committed scrollTop, not pending target', () => {
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const handle = {
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getPendingDelta: () => 24,
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getScrollHeight: () => 100,
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getScrollTop: () => 10,
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getViewportHeight: () => 20,
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isSticky: () => false
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}
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const viewport = getViewportSnapshot(handle as any)
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const scrollbar = getScrollbarSnapshot(handle as any)
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expect(viewport.top).toBe(34)
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expect(scrollbar).toEqual({
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scrollHeight: 100,
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top: 10,
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viewportHeight: 20
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})
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expect(scrollbarSnapshotKey(scrollbar)).toBe('10:20:100')
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})
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it('clamps scrollbar position to committed scroll bounds', () => {
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const handle = {
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getScrollHeight: () => 30,
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getScrollTop: () => 50,
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getViewportHeight: () => 20
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}
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expect(getScrollbarSnapshot(handle as any).top).toBe(10)
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})
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it('uses fresh scroll height to clear stale scrollbar non-bottom state after shrink', () => {
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const handle = {
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getFreshScrollHeight: () => 40,
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getScrollHeight: () => 60,
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getScrollTop: () => 20,
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getViewportHeight: () => 20
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}
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const snap = getScrollbarSnapshot(handle as any)
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expect(snap).toEqual({
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scrollHeight: 40,
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top: 20,
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viewportHeight: 20
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})
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expect(scrollbarSnapshotKey(snap)).toBe('20:20:40')
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})
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})
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