import { DIRECTION_UP, PROBE_REALTIME } from '../util/const'
export function pullUpMixin(BScroll) {
BScroll.prototype._initPullUp = function () {
// must watch scroll in real time
this.options.probeType = PROBE_REALTIME
this.pullupWatching = false
this._watchPullUp()
}
BScroll.prototype._watchPullUp = function () {
Iif (this.pullupWatching) {
return
}
this.pullupWatching = true
this.on('scroll', this._checkToEnd)
}
BScroll.prototype._checkToEnd = function (pos) {
const {threshold = 0} = this.options.pullUpLoad
if (this.movingDirectionY === DIRECTION_UP && pos.y <= (this.maxScrollY + threshold)) {
// reset pullupWatching status after scroll end.
this.once('scrollEnd', () => {
this.pullupWatching = false
})
this.trigger('pullingUp')
this.off('scroll', this._checkToEnd)
}
}
BScroll.prototype.finishPullUp = function () {
Iif (this.pullupWatching) {
this.once('scrollEnd', () => {
this._watchPullUp()
})
} else {
this._watchPullUp()
}
}
BScroll.prototype.openPullUp = function (config = true) {
this.options.pullUpLoad = config
this._initPullUp()
}
BScroll.prototype.closePullUp = function () {
this.options.pullUpLoad = false
if (!this.pullupWatching) {
return
}
this.pullupWatching = false
this.off('scroll', this._checkToEnd)
}
}
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