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Switch Promise chaining to async-await syntax. #82

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Merged
merged 5 commits into from
Oct 31, 2022
Merged

Switch Promise chaining to async-await syntax. #82

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2fb836c
Switch `Promise` chaining to `async`-`await` syntax.
lgarron Oct 28, 2022
4b6a263
Consolidate task calls.
lgarron Oct 28, 2022
d7f560c
Switch to `for`-`of` per the linter.
lgarron Oct 28, 2022
fcff398
Fixups.
lgarron Oct 28, 2022
d3f7b4d
Update src/index.ts
lgarron Oct 31, 2022
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115 changes: 52 additions & 63 deletions src/index.ts
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Original file line number Diff line number Diff line change
@@ -1,10 +1,5 @@
const privateData = new WeakMap()

// Functional stand in for the W3 spec "queue a task" paradigm
function task(): Promise<void> {
return new Promise(resolve => setTimeout(resolve, 0))
}

function isWildcard(accept: string | null) {
return accept && !!accept.split(',').find(x => x.match(/^\s*\*\/\*/))
}
Expand Down Expand Up @@ -133,28 +128,26 @@ export default class IncludeFragmentElement extends HTMLElement {
}
)

#handleData(): Promise<void> {
if (this.#busy) return Promise.resolve()
async #handleData(): Promise<void> {
if (this.#busy) return
this.#busy = true

this.#observer.unobserve(this)
return this.#getData().then(
(html: string) => {
const template = document.createElement('template')
// eslint-disable-next-line github/no-inner-html
template.innerHTML = html
const fragment = document.importNode(template.content, true)
const canceled = !this.dispatchEvent(
new CustomEvent('include-fragment-replace', {cancelable: true, detail: {fragment}})
)
if (canceled) return
this.replaceWith(fragment)
this.dispatchEvent(new CustomEvent('include-fragment-replaced'))
},
() => {
this.classList.add('is-error')
}
)
try {
const html = await this.#getData()

const template = document.createElement('template')
// eslint-disable-next-line github/no-inner-html
template.innerHTML = html
const fragment = document.importNode(template.content, true)
const canceled = !this.dispatchEvent(
new CustomEvent('include-fragment-replace', {cancelable: true, detail: {fragment}})
)
if (canceled) return
this.replaceWith(fragment)
this.dispatchEvent(new CustomEvent('include-fragment-replaced'))
} catch {
this.classList.add('is-error')
}
}

#getData(): Promise<string> {
Expand All @@ -173,47 +166,43 @@ export default class IncludeFragmentElement extends HTMLElement {
}
}

#fetchDataWithEvents(): Promise<string> {
// Functional stand in for the W3 spec "queue a task" paradigm
async #task(eventsToDispatch: string[]): Promise<void> {
await new Promise(resolve => setTimeout(resolve, 0))
for (const eventType of eventsToDispatch) {
this.dispatchEvent(new Event(eventType))
}
}

async #fetchDataWithEvents(): Promise<string> {
// We mimic the same event order as <img>, including the spec
// which states events must be dispatched after "queue a task".
// https://www.w3.org/TR/html52/semantics-embedded-content.html#the-img-element
return task()
.then(() => {
this.dispatchEvent(new Event('loadstart'))
return this.fetch(this.request())
})
.then(response => {
if (response.status !== 200) {
throw new Error(`Failed to load resource: the server responded with a status of ${response.status}`)
}
const ct = response.headers.get('Content-Type')
if (!isWildcard(this.accept) && (!ct || !ct.includes(this.accept ? this.accept : 'text/html'))) {
throw new Error(`Failed to load resource: expected ${this.accept || 'text/html'} but was ${ct}`)
}
return response.text()
})
.then(
data => {
// Dispatch `load` and `loadend` async to allow
// the `load()` promise to resolve _before_ these
// events are fired.
task().then(() => {
this.dispatchEvent(new Event('load'))
this.dispatchEvent(new Event('loadend'))
})
return data
},
error => {
// Dispatch `error` and `loadend` async to allow
// the `load()` promise to resolve _before_ these
// events are fired.
task().then(() => {
this.dispatchEvent(new Event('error'))
this.dispatchEvent(new Event('loadend'))
})
throw error
}
)

await this.#task(['loadstart'])
const response = await this.fetch(this.request())
if (response.status !== 200) {
throw new Error(`Failed to load resource: the server responded with a status of ${response.status}`)
}
const ct = response.headers.get('Content-Type')
if (!isWildcard(this.accept) && (!ct || !ct.includes(this.accept ? this.accept : 'text/html'))) {
throw new Error(`Failed to load resource: expected ${this.accept || 'text/html'} but was ${ct}`)
}
const data = await response.text()

try {
// Dispatch `load` and `loadend` async to allow
// the `load()` promise to resolve _before_ these
// events are fired.
this.#task(['load', 'loadend'])
return data
} catch (error) {
// Dispatch `error` and `loadend` async to allow
// the `load()` promise to resolve _before_ these
// events are fired.
this.#task(['error', 'loadend'])
throw error
}
}
}

Expand Down