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feat: refactor #37

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feat: refactor #37

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2 changes: 1 addition & 1 deletion package.json
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
{
"name": "vue3-lazyload",
"version": "0.3.6",
"version": "0.4.0-refactored",
"packageManager": "pnpm@6.32.3",
"description": "A Vue3.x image lazyload plugin",
"license": "MIT",
Expand Down
114 changes: 67 additions & 47 deletions src/lazy.ts
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Original file line number Diff line number Diff line change
@@ -1,5 +1,3 @@
/* eslint-disable @typescript-eslint/explicit-module-boundary-types */
/* eslint-disable @typescript-eslint/no-empty-function */
import type { DirectiveBinding } from 'vue-demi'
import type { LazyOptions, Lifecycle, ValueFormatterObject } from './types'
import { LifecycleEnum } from './types'
Expand Down Expand Up @@ -57,13 +55,7 @@ export default class Lazy {
const { src, loading, error, lifecycle, delay } = this._valueFormatter(typeof binding === 'string' ? binding : binding.value)
this._lifecycle(LifecycleEnum.LOADING, lifecycle, el)
el.setAttribute('src', loading || DEFAULT_LOADING)
if (!hasIntersectionObserver) {
this.loadImages(el, src, error, lifecycle)
this._log(() => {
throw new Error('Not support IntersectionObserver!')
})
}
this._initIntersectionObserver(el, src, error, lifecycle, delay)
this._tryInitIntersectionObserver(el, src, loading, error, lifecycle, delay)
}

/**
Expand All @@ -76,8 +68,8 @@ export default class Lazy {
if (!el)
return
this._realObserver(el)?.unobserve(el)
const { src, error, lifecycle, delay } = this._valueFormatter(typeof binding === 'string' ? binding : binding.value)
this._initIntersectionObserver(el, src, error, lifecycle, delay)
const { src, loading, error, lifecycle, delay } = this._valueFormatter(typeof binding === 'string' ? binding : binding.value)
this._tryInitIntersectionObserver(el, src, loading, error, lifecycle, delay)
}

/**
Expand All @@ -93,51 +85,79 @@ export default class Lazy {
this._images.delete(el)
}

private _tryLoadImage(el: HTMLElement, src: string, onSuccess: ((this: GlobalEventHandlers, ev: Event) => any) | null, onError: OnErrorEventHandler) {
const img = new Image()
img.src = src

const _onSuccess = el
? (...p) => {
this._setImageSrc(el, src)
if (onSuccess)
// eslint-disable-next-line prefer-spread
onSuccess.apply(undefined, p)
}
: onSuccess

this._listenImageStatus(img, _onSuccess, onError)

return img
}

/**
* force loading
* update image with full lifecycles
*
* @param {HTMLElement} el
* @param {string} src
* @memberof Lazy
*/
public loadImages(el: HTMLElement, src: string, error?: string, lifecycle?: Lifecycle): void {
this._setImageSrc(el, src, error, lifecycle)
public loadImage(el: HTMLElement, src: string, loading?: string, error?: string, lifecycle?: Lifecycle): void {
const onSuccess = () => {
this._lifecycle(LifecycleEnum.LOADED, lifecycle, el)
}

const onError = () => {
this._listenImageStatus(el, null, null)
this._realObserver(el)?.unobserve(el)

this._lifecycle(LifecycleEnum.ERROR, lifecycle, el)
if (error || DEFAULT_ERROR)
this._setImageSrc(el, error || DEFAULT_ERROR)

this._log(() => {
throw new Error(`Image failed to load! And failed src was: ${src} `)
})
}

// loading state
this._lifecycle(LifecycleEnum.LOADING, lifecycle, el)
this._setImageSrc(el, loading || DEFAULT_LOADING)

this._tryLoadImage(el, src, onSuccess, onError)
}

/**
* set img tag src
* set img src
*
* @private
* @param {HTMLElement} el
* @param {string} src
* @memberof Lazy
*/
private _setImageSrc(el: HTMLElement, src: string, error?: string, lifecycle?: Lifecycle): void {
if (el.tagName.toLowerCase() === 'img') {
if (src) {
const preSrc = el.getAttribute('src')
if (preSrc !== src)
el.setAttribute('src', src)
}
this._listenImageStatus(el as HTMLImageElement, () => {
this._lifecycle(LifecycleEnum.LOADED, lifecycle, el)
}, () => {
// Fix onload trigger twice, clear onload event
// Reload on update
el.onload = null
this._lifecycle(LifecycleEnum.ERROR, lifecycle, el)
this._realObserver(el)?.disconnect()
if (error) {
const newImageSrc = el.getAttribute('src')
if (newImageSrc !== error)
el.setAttribute('src', error)
}
this._log(() => { throw new Error(`Image failed to load!And failed src was: ${src} `) })
})
}
else {
private _setImageSrc(el: HTMLElement, src: string): void {
if (el.tagName.toLowerCase() === 'img')
el.setAttribute('src', src)
else
el.style.backgroundImage = `url('${src}')`
}

private _tryInitIntersectionObserver(el: HTMLElement, src: string, loading?: string, error?: string, lifecycle?: Lifecycle, delay?: number): void {
if (!hasIntersectionObserver) {
this.loadImage(el, src, loading, error, lifecycle)
this._log(() => {
throw new Error('Not support IntersectionObserver!')
})
}
this._initIntersectionObserver(el, src, loading, error, lifecycle, delay)
}

/**
Expand All @@ -148,33 +168,33 @@ export default class Lazy {
* @param {string} src
* @memberof Lazy
*/
private _initIntersectionObserver(el: HTMLElement, src: string, error?: string, lifecycle?: Lifecycle, delay?: number): void {
private _initIntersectionObserver(el: HTMLElement, src: string, loading?: string, error?: string, lifecycle?: Lifecycle, delay?: number): void {
const observerOptions = this.options.observerOptions
this._images.set(el, new IntersectionObserver((entries) => {
Array.prototype.forEach.call(entries, (entry) => {
if (delay && delay > 0)
this._delayedIntersectionCallback(el, entry, delay, src, error, lifecycle)
this._delayedIntersectionCallback(el, entry, delay, src, loading, error, lifecycle)
else
this._intersectionCallback(el, entry, src, error, lifecycle)
this._intersectionCallback(el, entry, src, loading, error, lifecycle)
})
}, observerOptions))
this._realObserver(el)?.observe(el)
}

private _intersectionCallback(el: HTMLElement, entry: IntersectionObserverEntry, src: string, error?: string, lifecycle?: Lifecycle): void {
private _intersectionCallback(el: HTMLElement, entry: IntersectionObserverEntry, src: string, loading?: string, error?: string, lifecycle?: Lifecycle): void {
if (entry.isIntersecting) {
this._realObserver(el)?.unobserve(entry.target)
this._setImageSrc(el, src, error, lifecycle)
this.loadImage(el, src, loading, error, lifecycle)
}
}

private _delayedIntersectionCallback(el: HTMLElement, entry: IntersectionObserverEntry, delay: number, src: string, error?: string, lifecycle?: Lifecycle): void {
private _delayedIntersectionCallback(el: HTMLElement, entry: IntersectionObserverEntry, delay: number, src: string, loading?: string, error?: string, lifecycle?: Lifecycle): void {
if (entry.isIntersecting) {
if (entry.target.hasAttribute(TIMEOUT_ID_DATA_ATTR))
return

const timeoutId = setTimeout(() => {
this._intersectionCallback(el, entry, src, error, lifecycle)
this._intersectionCallback(el, entry, src, loading, error, lifecycle)
entry.target.removeAttribute(TIMEOUT_ID_DATA_ATTR)
}, delay)
entry.target.setAttribute(TIMEOUT_ID_DATA_ATTR, String(timeoutId))
Expand All @@ -197,7 +217,7 @@ export default class Lazy {
* @param {() => void} error
* @memberof Lazy
*/
private _listenImageStatus(image: HTMLImageElement, success: ((this: GlobalEventHandlers, ev: Event) => any) | null, error: OnErrorEventHandler) {
private _listenImageStatus(image: HTMLImageElement | HTMLElement, success: ((this: GlobalEventHandlers, ev: Event) => any) | null, error: OnErrorEventHandler) {
image.onload = success
image.onerror = error
}
Expand Down