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<script>
export default {
name: 'DynamicScrollerItem',
inject: [
'vscrollData',
'vscrollParent',
'vscrollResizeObserver',
],
props: {
// eslint-disable-next-line vue/require-prop-types
item: {
required: true,
},
watchData: {
type: Boolean,
default: false,
},
/**
* Indicates if the view is actively used to display an item.
*/
active: {
type: Boolean,
required: true,
},
index: {
type: Number,
default: undefined,
},
sizeDependencies: {
type: [Array, Object],
default: null,
},
emitResize: {
type: Boolean,
default: false,
},
tag: {
type: String,
default: 'div',
},
},
computed: {
id () {
return this.vscrollData.simpleArray ? this.index : this.item[this.vscrollData.keyField]
},
size () {
return (this.vscrollData.validSizes[this.id] && this.vscrollData.sizes[this.id]) || 0
},
finalActive () {
return this.active && this.vscrollData.active
},
},
watch: {
watchData: 'updateWatchData',
id () {
if (!this.size) {
this.onDataUpdate()
}
},
finalActive (value) {
if (!this.size) {
if (value) {
if (!this.vscrollParent.$_undefinedMap[this.id]) {
this.vscrollParent.$_undefinedSizes++
this.vscrollParent.$_undefinedMap[this.id] = true
}
} else {
if (this.vscrollParent.$_undefinedMap[this.id]) {
this.vscrollParent.$_undefinedSizes--
this.vscrollParent.$_undefinedMap[this.id] = false
}
}
}
if (this.vscrollResizeObserver) {
if (value) {
this.observeSize()
} else {
this.unobserveSize()
}
} else if (value && this.$_pendingVScrollUpdate === this.id) {
this.updateSize()
}
},
},
created () {
if (this.$isServer) return
this.$_forceNextVScrollUpdate = null
this.updateWatchData()
if (!this.vscrollResizeObserver) {
for (const k in this.sizeDependencies) {
this.$watch(() => this.sizeDependencies[k], this.onDataUpdate)
}
this.vscrollParent.$on('vscroll:update', this.onVscrollUpdate)
this.vscrollParent.$on('vscroll:update-size', this.onVscrollUpdateSize)
}
},
mounted () {
if (this.vscrollData.active) {
this.updateSize()
this.observeSize()
}
},
beforeDestroy () {
this.vscrollParent.$off('vscroll:update', this.onVscrollUpdate)
this.vscrollParent.$off('vscroll:update-size', this.onVscrollUpdateSize)
this.unobserveSize()
},
methods: {
updateSize () {
if (this.finalActive) {
if (this.$_pendingSizeUpdate !== this.id) {
this.$_pendingSizeUpdate = this.id
this.$_forceNextVScrollUpdate = null
this.$_pendingVScrollUpdate = null
this.computeSize(this.id)
}
} else {
this.$_forceNextVScrollUpdate = this.id
}
},
updateWatchData () {
if (this.watchData) {
this.$_watchData = this.$watch('data', () => {
this.onDataUpdate()
}, {
deep: true,
})
} else if (this.$_watchData) {
this.$_watchData()
this.$_watchData = null
}
},
onVscrollUpdate ({ force }) {
// If not active, sechedule a size update when it becomes active
if (!this.finalActive && force) {
this.$_pendingVScrollUpdate = this.id
}
if (this.$_forceNextVScrollUpdate === this.id || force || !this.size) {
this.updateSize()
}
},
onDataUpdate () {
this.updateSize()
},
computeSize (id) {
this.$nextTick(() => {
if (this.id === id) {
const width = this.$el.offsetWidth
const height = this.$el.offsetHeight
this.applySize(width, height)
}
this.$_pendingSizeUpdate = null
})
},
applySize (width, height) {
const size = Math.round(this.vscrollParent.direction === 'vertical' ? height : width)
if (size && this.size !== size) {
if (this.vscrollParent.$_undefinedMap[this.id]) {
this.vscrollParent.$_undefinedSizes--
this.vscrollParent.$_undefinedMap[this.id] = undefined
}
this.$set(this.vscrollData.sizes, this.id, size)
this.$set(this.vscrollData.validSizes, this.id, true)
if (this.emitResize) this.$emit('resize', this.id)
}
},
observeSize () {
if (!this.vscrollResizeObserver) return
this.vscrollResizeObserver.observe(this.$el.parentNode)
this.$el.parentNode.addEventListener('resize', this.onResize)
},
unobserveSize () {
if (!this.vscrollResizeObserver) return
this.vscrollResizeObserver.unobserve(this.$el.parentNode)
this.$el.parentNode.removeEventListener('resize', this.onResize)
},
onResize (event) {
const { width, height } = event.detail.contentRect
this.applySize(width, height)
},
},
render (h) {
return h(this.tag, this.$slots.default)
},
}
</script>
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