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2017-07-19 16:47:17 +00:00
export class TouchController {
x: number
y: number
threshold: number
leftSwipe: Function
rightSwipe: Function
upSwipe: Function
downSwipe: Function
constructor() {
document.addEventListener("touchstart", evt => this.handleTouchStart(evt), false)
document.addEventListener("touchmove", evt => this.handleTouchMove(evt), false)
this.downSwipe = this.upSwipe = this.rightSwipe = this.leftSwipe = () => null
this.threshold = 5
}
handleTouchStart(evt) {
this.x = evt.touches[0].clientX
this.y = evt.touches[0].clientY
}
handleTouchMove(evt) {
if(!this.x || !this.y) {
return
}
let xUp = evt.touches[0].clientX
let yUp = evt.touches[0].clientY
let xDiff = this.x - xUp
let yDiff = this.y - yUp
if(Math.abs(xDiff) > Math.abs(yDiff)) {
if(xDiff > this.threshold) {
this.leftSwipe()
} else if(xDiff < -this.threshold) {
this.rightSwipe()
}
} else {
if(yDiff > this.threshold) {
this.upSwipe()
} else if(yDiff < -this.threshold) {
this.downSwipe()
}
}
this.x = undefined
this.y = undefined
}
}