Bendik Aagaard LynghaugandClaude Fable 5
22c5045c25
toStream(location, state) renders to a web-standard ReadableStream of UTF-8 bytes: pass it to new Response() on web servers or Readable.fromWeb().pipe(res) on Node. It awaits store prefetch promises (state.prefetch, the pattern the #653 thread wanted standardized) and lazy route views before rendering, then flushes template output progressively through async holes. lazy(loader, loadingView?) wraps a dynamic import as a route handler: loads once, caches forever, renders the loading view (or holds the current tree via a placeholder) while in flight, emits render on arrival. toString() refuses lazy routes and prefetching stores with pointers to toStream() — both halves of the async-route story ship together, unlike the original PR. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_014NgfSjHE11oFpoSnLVKLXd
83 lines
2.9 KiB
JavaScript
83 lines
2.9 KiB
JavaScript
// Lazy routes in the browser (happy-dom): loading view while the module
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// is in flight, morph to the real view on arrival, PENDING keeps the
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// current tree during route changes, view cached after first load.
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import { test, before } from 'node:test'
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import assert from 'node:assert'
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import { Window } from 'happy-dom'
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let choo, lazy, html
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before(async () => {
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const win = new Window({ url: 'http://localhost/' })
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globalThis.window = win
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globalThis.document = win.document
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globalThis.requestAnimationFrame = win.requestAnimationFrame.bind(win)
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;({ default: choo, lazy } = await import('@choojs/core'))
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;({ default: html } = await import('@choojs/html/browser'))
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})
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const tick = (ms = 30) => new Promise((resolve) => setTimeout(resolve, ms))
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test('lazy route with a loading view: loading first, real view after', async () => {
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let resolveLoader
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const loaderDone = new Promise((resolve) => { resolveLoader = resolve })
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const app = choo()
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app.route('/', lazy(
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() => loaderDone,
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() => html`<div><p>loading…</p></div>`
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))
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const tree = app.start()
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assert.strictEqual(tree.textContent, 'loading…', 'loading view rendered while in flight')
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resolveLoader({ default: (state) => html`<div><p>arrived</p></div>` })
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await tick()
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assert.strictEqual(tree.textContent, 'arrived', 'real view morphed in over the loading view')
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})
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test('lazy route without a loading view: placeholder, then wholesale replace', async () => {
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let resolveLoader
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const loaderDone = new Promise((resolve) => { resolveLoader = resolve })
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const app = choo()
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app.route('/', lazy(() => loaderDone))
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const tree = app.start()
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assert.ok(tree.hasAttribute('data-choo-pending'), 'placeholder holds the spot')
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document.body.appendChild(tree)
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resolveLoader({ default: (state) => html`<main><h1>real</h1></main>` })
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await tick()
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assert.strictEqual(document.querySelector('main h1').textContent, 'real', 'real view replaced the placeholder in the DOM')
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assert.strictEqual(document.querySelector('[data-choo-pending]'), null, 'placeholder gone')
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document.querySelector('main').remove()
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})
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test('loaded lazy views render synchronously ever after', async () => {
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const view = (state) => html`<div>cached ${state.count}</div>`
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const wrapped = lazy(() => Promise.resolve({ default: view }))
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const app = choo()
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app.use((state, emitter) => {
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state.count = 0
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emitter.on('bump', () => { state.count++; emitter.emit('render') })
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})
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app.route('/', wrapped)
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// no loading view: the placeholder must live in the DOM to be replaced
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const holder = document.createElement('section')
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document.body.appendChild(holder)
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holder.appendChild(app.start())
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await tick() // let the loader resolve + re-render
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assert.strictEqual(holder.textContent, 'cached 0')
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app.emit('bump')
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await tick()
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assert.strictEqual(holder.textContent, 'cached 1', 'subsequent renders are sync through the cache')
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holder.remove()
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})
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