76 lines
2.6 KiB
TypeScript
76 lines
2.6 KiB
TypeScript
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/**
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* Notifier: microtask batching, rebuild-before-notify ordering, no-listener
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* laziness, synchronous notifyNow, and unsubscribe.
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*/
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import { describe, expect, it } from 'vitest'
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import { Notifier } from '../src/client/sessions/notifier.ts'
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const microtask = (): Promise<void> => new Promise((resolve) => { queueMicrotask(resolve) })
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describe('Notifier', () => {
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it('collapses N markDirty calls into one flush, rebuilding before notifying', async () => {
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const order: string[] = []
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const notifier = new Notifier(() => order.push('rebuild'))
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notifier.subscribe(() => order.push('notify'))
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notifier.markDirty()
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notifier.markDirty()
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notifier.markDirty()
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expect(order).toEqual([]) // nothing until the microtask boundary
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await microtask()
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expect(order).toEqual(['rebuild', 'notify'])
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})
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it('skips rebuild with zero listeners and ensureFresh rebuilds lazily exactly once', async () => {
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let rebuilds = 0
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const notifier = new Notifier(() => { rebuilds++ })
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notifier.markDirty()
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await microtask()
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expect(rebuilds).toBe(0) // lazy: kept dirty
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notifier.ensureFresh()
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expect(rebuilds).toBe(1)
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notifier.ensureFresh()
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expect(rebuilds).toBe(1) // clean: no second rebuild
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})
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it('notifyNow runs listeners synchronously (controlled-input contract)', () => {
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const order: string[] = []
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const notifier = new Notifier(() => order.push('rebuild'))
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notifier.subscribe(() => order.push('notify'))
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notifier.notifyNow()
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expect(order).toEqual(['rebuild', 'notify']) // before returning, no microtask needed
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})
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it('notifyNow with zero listeners stays lazy like markDirty', () => {
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let rebuilds = 0
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const notifier = new Notifier(() => { rebuilds++ })
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notifier.notifyNow()
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expect(rebuilds).toBe(0)
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notifier.ensureFresh()
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expect(rebuilds).toBe(1)
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})
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it('a scheduled flush after notifyNow already flushed is a no-op', async () => {
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let rebuilds = 0
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const notifier = new Notifier(() => { rebuilds++ })
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notifier.subscribe(() => undefined)
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notifier.markDirty() // schedules the microtask flush
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notifier.notifyNow() // flushes synchronously, clears dirty
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await microtask() // the scheduled flush finds dirty=false
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expect(rebuilds).toBe(1)
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})
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it('unsubscribed listeners stop receiving notifications', async () => {
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let calls = 0
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const notifier = new Notifier(() => undefined)
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const unsubscribe = notifier.subscribe(() => { calls++ })
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notifier.notifyNow()
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expect(calls).toBe(1)
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unsubscribe()
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notifier.markDirty()
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await microtask()
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notifier.notifyNow()
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expect(calls).toBe(1)
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})
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})
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