src/ol/pointer/TouchSource.js
function touchstart(inEvent) {
  this.vacuumTouches_(inEvent);
  this.setPrimaryTouch_(inEvent.changedTouches[0]);
  this.dedupSynthMouse_(inEvent);
  this.clickCount_++;
  this.processTouches_(inEvent, this.overDown_);
}
function touchstart(inEvent) {
  this.vacuumTouches_(inEvent);
  this.setPrimaryTouch_(inEvent.changedTouches[0]);
  this.dedupSynthMouse_(inEvent);
  this.clickCount_++;
  this.processTouches_(inEvent, this.overDown_);
}
function touchstart ( inEvent ) { this . vacuumTouches_ ( inEvent ) ; this . setPrimaryTouch_ ( inEvent . changedTouches [ 0 ] ) ; this . dedupSynthMouse_ ( inEvent ) ; this . clickCount_ ++ ; this . processTouches_ ( inEvent , this . overDown_ ) ; }
Handler for `touchstart`, triggers `pointerover`,
`pointerenter` and `pointerdown` events.

@this {TouchSource}
@param {TouchEvent} inEvent The in event.
Handler for touchstart triggers pointerover pointerenter and pointerdown events .