Salah 0.5: defer center resizing until scrolling stops

tests/focus.cjs

@@ -9,21 +9,21 @@ const p = Object.assign({}, ctx.spec, JSON.parse(JSON.stringify(ctx.spec.private
 p.update()
 assert.equal(typeof p.onScroll, 'function', 'scroll handler drives center magnification')
 const size = i => parseFloat(p.rows[i].timeStyle.fontSize)
-p.onScroll({scrollY: 0})
+p.onScroll({scrollY: 0, scrollState: 0})
 assert.equal(size(0), 60, 'first centered prayer gets 60px time')
 assert.ok(size(1) < size(0))
-p.onScroll({scrollY: 104})
+p.onScroll({scrollY: 104, scrollState: 0})
 assert.equal(size(1), 60)
 assert.equal(size(0), size(2), 'symmetric shrink around center')
-p.onScroll({scrollY: 52})
-assert.equal(size(0), size(1), 'continuous interpolation between rows')
-assert.ok(size(0) > 30 && size(0) < 60)
-p.onScroll({scrollY: 520})
+p.onScroll({scrollY: 52, scrollState: 0})
+assert.equal(size(1), 60, 'nearest row wins after stopping halfway')
+assert.equal(size(0), 30)
+p.onScroll({scrollY: 520, scrollState: 0})
 assert.equal(size(5), 60, 'last prayer can be magnified')
 p.update()
 assert.equal(size(5), 60, 'clock refresh preserves scroll focus')
 for (const offset of [-100, 9999]) {
- p.onScroll({scrollY: offset})
+ p.onScroll({scrollY: offset, scrollState: 0})
  p.rows.forEach(row => assert.ok(parseFloat(row.timeStyle.fontSize) >= 30 && parseFloat(row.timeStyle.fontSize) <= 60))
 }
 const before = JSON.stringify(p.rows)
@@ -37,4 +37,4 @@ function css(c,k) { return parseFloat(src.match(new RegExp('\\.'+c+'\\s*\\{([^}]
 assert.equal(css('prayers','top') + css('prayers','height') / 2, 233, 'magnification center is physical screen center')
 assert.equal(css('row','height'), 104, 'fixed row geometry prevents scroll feedback')
 assert.ok(css('clock','font-size') > 42, 'header clock enlarged too')
-console.log('Center magnification, interpolation, end rows, refresh preservation, invalid events and wiring passed')
+console.log('Center magnification, settled focus, end rows, refresh preservation, invalid events and wiring passed')

tests/scroll-performance.cjs

@@ -0,0 +1,38 @@
+const assert = require('node:assert/strict')
+const fs = require('node:fs')
+const vm = require('node:vm')
+const src = fs.readFileSync('src/pages/index/index.ux', 'utf8')
+const body = src.match(/<script>([\s\S]*?)<\/script>/)[1].replace(/import\s+\w+\s+from\s+'[^']*';?/, '').replace('export default', 'globalThis.spec =')
+const ctx = {prayer: require('../src/common/prayer.js'), setInterval: () => 1, clearInterval: () => {}}
+vm.createContext(ctx); vm.runInContext(body, ctx)
+const p = Object.assign({}, ctx.spec, JSON.parse(JSON.stringify(ctx.spec.private)))
+p.update()
+let rows = p.rows, writes = 0
+Object.defineProperty(p, 'rows', {get: () => rows, set: value => {writes++; rows = value}})
+const original = JSON.stringify(rows)
+for (let i=0; i<500; i++) p.onScroll({scrollY: i, scrollState: i < 250 ? 1 : 2})
+console.log('Row-array replacements during 500 gesture/inertia events:', writes)
+assert.equal(writes, 0, 'native scrolling must not rebuild reactive rows')
+assert.equal(JSON.stringify(rows), original, 'no font changes while scrolling')
+p.update()
+assert.equal(writes, 0, 'periodic refresh must defer during scrolling')
+p.onScroll({scrollY: 520, scrollState: 0})
+assert.equal(parseFloat(p.rows[5].timeStyle.fontSize), 60, 'last row grows after stop')
+assert.ok(writes <= 1, 'one focus update at stop')
+const settled = writes
+p.onScrollEnd()
+assert.equal(writes, settled, 'duplicate stop event is a no-op')
+p.onScroll({scrollY: 208, scrollState: 1})
+p.onScrollEnd()
+assert.equal(parseFloat(p.rows[2].timeStyle.fontSize), 60, 'scrollend fallback applies nearest row')
+assert.equal(parseFloat(p.rows[1].timeStyle.fontSize), 30)
+const saved = JSON.stringify(p.rows)
+for (const e of [undefined, {}, {scrollY: NaN}, {scrollY: Infinity}]) p.onScroll(e)
+assert.equal(JSON.stringify(p.rows), saved)
+p.onScroll({scrollY: 312, scrollState: 1})
+p.onHide()
+p.onShow()
+assert.equal(p._scrolling, false, 'hiding during a swipe must not freeze refresh after resume')
+assert.equal(parseFloat(p.rows[3].timeStyle.fontSize), 60)
+assert.match(src, /onscrollend="onScrollEnd"/)
+console.log('Scroll workload, deferred refresh, settled focus and duplicate-event checks passed')