A simple swipe detection on vanilla js

swipe.js

var touchstartX = 0;
var touchstartY = 0;
var touchendX = 0;
var touchendY = 0;

var gesuredZone = document.getElementById('gesuredZone');

gesuredZone.addEventListener('touchstart', function(event) {
    touchstartX = event.screenX;
    touchstartY = event.screenY;
}, false);

gesuredZone.addEventListener('touchend', function(event) {
    touchendX = event.screenX;
    touchendY = event.screenY;
    handleGesure();
}, false); 

function handleGesure() {
    var swiped = 'swiped: ';
    if (touchendX < touchstartX) {
        alert(swiped + 'left!');
    }
    if (touchendX > touchstartX) {
        alert(swiped + 'right!');
    }
    if (touchendY < touchstartY) {
        alert(swiped + 'down!');
    }
    if (touchendY > touchstartY) {
        alert(swiped + 'left!');
    }
    if (touchendY == touchstartY) {
        alert('tap!');
    }
}

Hello,

This api event.screen does not work any more.

Change to e.changedTouches[0].screenY; and e.changedTouches[0].screenX;

Also line 31 should say up.

Actually, in this script, it should be : event.changedTouches[0].screenY; and event.changedTouches[0].screenX;

THX
with some errors, but still better than jQuery

@SleepWalker also line 31 should be the 'up' direction

Useless.

Worked for me thanks! :)

Thanks! I made some small tweaks to this, based on the comments above:

let touchstartX = 0;
let touchstartY = 0;
let touchendX = 0;
let touchendY = 0;

const gestureZone = document.getElementById('gestureZone');

gestureZone.addEventListener('touchstart', function(event) {
    touchstartX = event.changedTouches[0].screenX;
    touchstartY = event.changedTouches[0].screenY;
}, false);

gestureZone.addEventListener('touchend', function(event) {
    touchendX = event.changedTouches[0].screenX;
    touchendY = event.changedTouches[0].screenY;
    handleGesture();
}, false); 

function handleGesture() {
    if (touchendX <= touchstartX) {
        console.log('Swiped left');
    }
    
    if (touchendX >= touchstartX) {
        console.log('Swiped right');
    }
    
    if (touchendY <= touchstartY) {
        console.log('Swiped up');
    }
    
    if (touchendY >= touchstartY) {
        console.log('Swiped down');
    }
    
    if (touchendY === touchstartY) {
        console.log('Tap');
    }
}

Thank you, it was very helpful!

Thx!

I have a different approach for the handleGesture ( does not include the tap though ) that works with the dimensions of the element that the events are occuring on ( because let's face it, users do not swipe in a straight line most of the time, and we should account for this )

const { width, height } = dom_el.getBoundingClientRect();

const ratio_horizontal = (end.screenX - start.screenX) / width;
const ratio_vertical = (end.screenY - start.screenY) / height;

if (ratio_horizontal > ratio_vertical && ratio_horizontal > 0.25) {
    return console.log('swipe-right');
}
if (ratio_vertical > ratio_horizontal && ratio_vertical > 0.25) {
    return console.log('swipe-down');
}
if (ratio_horizontal < ratio_vertical && ratio_horizontal < -0.25) {
    return console.log('swipe-left');
}
if (ratio_vertical < ratio_horizontal && ratio_vertical < -0.25) {
    return console.log('swipe-up');
}

return false;

@mocon heads up on your revisions if you haven't already noticed

Seems to me that including using touchendX <= touchstartX etc instead of touchendX < touchstartX etc in the handleGesture code means that any "tap" will also register every swipe event

@IanRr thanks for that correction. @mocon thanks for tweak
It works fine now

let touchstartX = 0;
let touchstartY = 0;
let touchendX = 0;
let touchendY = 0;

const gestureZone = document.getElementById('modalContent');

gestureZone.addEventListener('touchstart', function(event) {
    touchstartX = event.changedTouches[0].screenX;
    touchstartY = event.changedTouches[0].screenY;
}, false);

gestureZone.addEventListener('touchend', function(event) {
    touchendX = event.changedTouches[0].screenX;
    touchendY = event.changedTouches[0].screenY;
    handleGesture();
}, false); 

function handleGesture() {
    if (touchendX < touchstartX) {
        console.log('Swiped left');
    }
    
    if (touchendX > touchstartX) {
        console.log('Swiped right');
    }
    
    if (touchendY < touchstartY) {
        console.log('Swiped up');
    }
    
    if (touchendY > touchstartY) {
       console.log('Swiped down');
    }
    
    if (touchendY === touchstartY) {
       console.log('Tap');
    }
}

Small modification of @stephenjude using angles (45° for each of the 8 directions) to determine the direction and a treshold of 1px or 1% of page width:

let pageWidth = window.innerWidth || document.body.clientWidth;
let treshold = Math.max(1,Math.floor(0.01 * (pageWidth)));
let touchstartX = 0;
let touchstartY = 0;
let touchendX = 0;
let touchendY = 0;

const limit = Math.tan(45 * 1.5 / 180 * Math.PI);
const gestureZone = document.getElementById('modalContent');

gestureZone.addEventListener('touchstart', function(event) {
    touchstartX = event.changedTouches[0].screenX;
    touchstartY = event.changedTouches[0].screenY;
}, false);

gestureZone.addEventListener('touchend', function(event) {
    touchendX = event.changedTouches[0].screenX;
    touchendY = event.changedTouches[0].screenY;
    handleGesture(event);
}, false);

function handleGesture(e) {
    let x = touchendX - touchstartX;
    let y = touchendY - touchstartY;
    let xy = Math.abs(x / y);
    let yx = Math.abs(y / x);
    if (Math.abs(x) > treshold || Math.abs(y) > treshold) {
        if (yx <= limit) {
            if (x < 0) {
                console.log("left");
            } else {
                console.log("right");
            }
        }
        if (xy <= limit) {
            if (y < 0) {
                console.log("top");
            } else {
                console.log("bottom");
            }
        }
    } else {
        console.log("tap");
    }
}

Like !

i add this script to npm

npm link:
https://www.npmjs.com/package/xwiper

github link:
https://github.com/uxitten/xwiper

Hello , actually won't work on some Android Chrome newer versions... If someone could add browser interogation for Pointer Events and a solution for the it , would be our hero !

Idk... I tried to modify uxitten approach with Pointer Events ... If someone could write a more elegant version of this with pinch and multiple taps would be awesome ...

class Xwiper {
    constructor(element) {
        this.element = null;
        this.touchStartX = 0;
        this.touchStartY = 0;
        this.touchEndX = 0;
        this.touchEndY = 0;
        this.touchMovedX = 0;
        this.touchMovedY = 0;
        this.sensitive = 5;
        this.onSwipeLeftAgent = null;
        this.onSwipeRightAgent = null;
        this.onSwipeUpAgent = null;
        this.onSwipeDownAgent = null;
        this.onTapAgent = null;
        this.onTouchStart = this.onTouchStart.bind(this);
        this.onTouchEnd = this.onTouchEnd.bind(this);
        this.onPointerStart = this.onPointerStart.bind(this);
        this.onPointerMoved = this.onPointerMoved.bind(this);
        this.onPointerEnd = this.onPointerEnd.bind(this);
        this.onSwipeLeft = this.onSwipeLeft.bind(this);
        this.onSwipeRight = this.onSwipeRight.bind(this);
        this.onSwipeUp = this.onSwipeUp.bind(this);
        this.onSwipeDown = this.onSwipeDown.bind(this);
        this.onTap = this.onTap.bind(this);
        this.destroy = this.destroy.bind(this);
        this.handleGesture = this.handleGesture.bind(this);

        this.element = document.querySelector(element);
		if (window.PointerEvent) {
			this.element.addEventListener( 'pointerdown', this.onPointerStart,false);

			this.element.addEventListener( 'pointermove', this.onPointerMoved,false);
				
			this.element.addEventListener( 'pointercancel', this.onPointerEnd,false);
		} else {
			this.element.addEventListener('touchstart', this.onTouchStart ,false);
			this.element.addEventListener('touchend', this.onTouchEnd, false);	
		}
    }

    onTouchStart(event) {
        this.touchStartX = event.changedTouches[0].screenX;
        this.touchStartY = event.changedTouches[0].screenY;
    }

    onTouchEnd(event) {
        this.touchEndX = event.changedTouches[0].screenX;
        this.touchEndY = event.changedTouches[0].screenY;
        this.handleGesture();
    }

    onPointerStart(event) {
		switch ( event.pointerType ) {
			case 'mouse':
				//add code
			break;

			case 'touch':
				this.touchStartX = event.screenX;
				this.touchStartY = event.screenY;
			break;
			case 'pen':
				//add code
			break;
			default:
				//add code
			break;
			}
    }

    onPointerMoved(event) {
		switch ( event.pointerType ) {
			case 'mouse':
				//add code
			break;
			case 'touch':
				this.touchMovedX = event.screenX;
				this.touchMovedY = event.screenY;
			break;
			case 'pen':
				//add code
			break;
			default:
				//add code
			break;
		}
    }
    onPointerEnd(event) {
		switch ( event.pointerType ) {
			case 'mouse':
				//add code
			break;

			case 'touch':
				this.touchEndX = this.touchMovedX;
				this.touchEndY = this.touchMovedY;
			break;

			case 'pen':
				//add code
			break;

			default:
				//add code
			break;
		}
        this.handleGesture();
    }

    onSwipeLeft(func) {
        this.onSwipeLeftAgent = func;
    }
    onSwipeRight(func) {
        this.onSwipeRightAgent = func;
    }
    onSwipeUp(func) {
        this.onSwipeUpAgent = func;
    }
    onSwipeDown(func) {
        this.onSwipeDownAgent = func;
    }
    onTap(func) {
        this.onTapAgent = func;
    }

    destroy() {
        this.element.removeEventListener('touchstart', this.onTouchStart);
        this.element.removeEventListener('touchend', this.onTouchEnd);
        this.element.removeEventListener('pointerstart', this.onTouchStart);
        this.element.removeEventListener('pointermove', this.onTouchMove);
        this.element.removeEventListener('touchover', this.onTouchEnd);
    }

	handleGesture() {
        /**
         * swiped left
         */
        if (this.touchEndX + this.sensitive < this.touchStartX) {
            this.onSwipeLeftAgent &&
                this.onSwipeLeftAgent();
            return 'swiped left';
        }

        /**
         * swiped right
         */
        if (this.touchEndX - this.sensitive > this.touchStartX) {
            this.onSwipeRightAgent &&
                this.onSwipeRightAgent();
            return 'swiped right';
        }

        /**
         * swiped up
         */
        if (this.touchEndY + this.sensitive < this.touchStartY) {
            this.onSwipeUpAgent &&
                this.onSwipeUpAgent();
            return 'swiped up';
        }

        /**
         * swiped down
         */
        if (this.touchEndY - this.sensitive > this.touchStartY) {
            this.onSwipeDownAgent &&
                this.onSwipeDownAgent();
            return 'swiped down';
        }

        /**
         * tap
         */
        if (this.touchEndY === this.touchStartY) {
            this.onTapAgent &&
                this.onTapAgent();
            return 'tap';
        }
    }
}

I took a shot at improving this too. I added multiple listeners support, long press, mouse support, velocity threshold, and customization. It's on NPM and GitHub:

https://www.npmjs.com/package/tinygesture
https://github.com/sciactive/tinygesture

Here's a demo:
https://sciactive.github.io/tinygesture/

Thank you @SleepWalker, @uxitten, @c7x43t.

Thank you so much.
Pretty usefull !~

Here I leave you some code I use, some of it was initially based on the code listed here, then modified to adjust to my needs and new events.

TlakDev.EventHandler.prototype._defaults = {
	touch: {
		x: 0,
		y: 0
	},
	touchEnd: {
		x: 0,
		y: 0
	}
}
TlakDev.EventHandler.prototype.sendTouchEvent = function (event, element) {
	let t = this;
	switch(true){
		case ((Math.abs(t.touch.x) - Math.abs(t.touchEnd.x)) === 0) && ((Math.abs(t.touch.y) - Math.abs(t.touchEnd.y)) === 0):
			event.direction = "tap";
		break;
		case Math.abs(t.touch.x - t.touchEnd.x) > Math.abs(t.touch.y - t.touchEnd.y):
			/*left/right*/
			if(t.touch.x > t.touchEnd.x){
				event.direction = "left";
			} else {
				event.direction = "right";
			}
		break;
		default:
			/*up/down*/
			if(t.touch.y < t.touchEnd.y){
				event.direction = "down";
			} else {
				event.direction = "up";
			}
		break;
	}
	switch(true){
		case ((Math.abs(t.touch.x) - Math.abs(t.touchEnd.x)) === 0) && ((Math.abs(t.touch.y) - Math.abs(t.touchEnd.y)) === 0):
			event.directionPrecision = "tap";
		break;
		case t.touch.x > t.touchEnd.x:
			/*left*/
			if(t.touch.y > t.touchEnd.y){
				event.directionPrecision = "upLeft";
			} else {
				event.directionPrecision = "downLeft";
			}
		break;
		default:
			/*right*/
			if(t.touch.y > t.touchEnd.y){
				event.directionPrecision = "upRight";
			} else {
				event.directionPrecision = "downRight";
			}
		break;
	}
	/*
	 * Do whatever you need with the event/element
	 * The event contains 2 properties
	 * 1. direction  = tap|left|right|up|down
	 * 2. directionPrecision tap|upRight|upLeft|downRight|downLeft
	*/
}
TlakDev.EventHandler.prototype.setTouch = function (event) {
	let e = {};
	if(event.screenY){
		e.x = event.screenX;
		e.y = event.screenY;
	} else if(typeof event.touches !== "undefined" && event.touches.length > 0){
		e.x = event.touches[0].pageX;
		e.y = event.touches[0].pageY;
	} else if(typeof event.changedTouches !== "undefined" && event.changedTouches.length > 0) {
		e.x = event.changedTouches[0].pageX;
		e.y = event.changedTouches[0].pageY;
	} else {
		e.x = 0;
		e.y = 0;
	}
	return e;
}
/*
@param nodes is an array of javascript elements to which apply the events
*/
TlakDev.EventHandler.prototype.handleSwipes = function (nodes) {
	let t = this;
	nodes.forEach(function(element){
		element.addEventListener("touchstart", function (event) {
			let e = t.setTouch(event);
			t.touch = e;
		});
		element.addEventListener("touchend", function (event) {
			let e = t.setTouch(event);
			t.touchEnd = e;
			t.sendTouchEvent(event, element);
		});
	});
}

Function that only listen the y down event.

`
var swipe = document.getElementById('swipe');

  var touchstartY = 0;
  var touchendY = 0;

  swipe.addEventListener('touchstart', function(event) {
    touchstartY = event.changedTouches[0].screenY;
  }, false);

  swipe.addEventListener('touchend', function(event) {
    touchendY = event.changedTouches[0].screenY;
      handleSwipe();
  }, false); 

  function handleSwipe() {
      var swiped = 'swiped: ';
      if (touchendY > touchstartY) {
          alert(swiped + 'down!');
      }
  }

`

Thanks a lot ;)

Thanks a lot it saved my day.

@IanRr thanks for that correction. @mocon thanks for tweak
It works fine now

let touchstartX = 0;
let touchstartY = 0;
let touchendX = 0;
let touchendY = 0;

const gestureZone = document.getElementById('modalContent');

gestureZone.addEventListener('touchstart', function(event) {
    touchstartX = event.changedTouches[0].screenX;
    touchstartY = event.changedTouches[0].screenY;
}, false);

gestureZone.addEventListener('touchend', function(event) {
    touchendX = event.changedTouches[0].screenX;
    touchendY = event.changedTouches[0].screenY;
    handleGesture();
}, false); 

function handleGesture() {
    if (touchendX < touchstartX) {
        console.log('Swiped left');
    }
    
    if (touchendX > touchstartX) {
        console.log('Swiped right');
    }
    
    if (touchendY < touchstartY) {
        console.log('Swiped up');
    }
    
    if (touchendY > touchstartY) {
       console.log('Swiped down');
    }
    
    if (touchendY === touchstartY) {
       console.log('Tap');
    }
}

THanks, man. It was really helpfull

This is starting to look like one of the leading script threads on vanillaJS touch events. Seems like Hammer, Zing and Interactjs (pointer events) libs (interact excluded) are maybe become a bit obsolete except for drag, drop, and pointer support. Does anyone have any flushed out changes they have made since (as the thread goes back a few years)? Would be cool to keep this thread up to date with any changes or learnings. Anyone using this extensively with event listeners on touchMove? @evrenakar @tlacaelelrl @hperrin

Everything is wrong .

if you swipe UP , Down , or Left Right it will trigger the action.

because its not checking the direction.

Its just checking the one point to another point on screen, and it can not determine the direction.
i will share new code once i fix this.
Thanks.

What did you change @vwebtech ?

I guess he means it will trigger multiple conditions, you can check which direction has the most bias:

let startX = 0;
let startY = 0;

function handleTouchStart(e) {
  startX = e.changedTouches[0].screenX;
  startY = e.changedTouches[0].screenY;
}

function handleTouchEnd(e) {
  const diffX = e.changedTouches[0].screenX - startX;
  const diffY = e.changedTouches[0].screenY - startY;
  const ratioX = Math.abs(diffX / diffY);
  const ratioY = Math.abs(diffY / diffX);
  const absDiff = Math.abs(ratioX > ratioY ? diffX : diffY);

  // Ignore small movements.
  if (absDiff < 30) {
    return;
  }

  if (ratioX > ratioY) {
    if (diffX >= 0) {
      console.log('right swipe');
    } else {
      console.log('left swipe');
    }
  } else {
    if (diffY >= 0) {
      console.log('down swipe');
    } else {
      console.log('up swipe');
    }
  }
}

hello people, the 0 in the changedTouches property stands for the number of touches i guess, meaning the number of fingers needed to detect the event? please help, i cannot find proper answers online (Or at least answers i understand...)...
Thanks

I guess he means it will trigger multiple conditions, you can check which direction has the most bias:

let startX = 0;
let startY = 0;

function handleTouchStart(e) {
  startX = e.changedTouches[0].screenX;
  startY = e.changedTouches[0].screenY;
}

function handleTouchEnd(e) {
  const diffX = e.changedTouches[0].screenX - startX;
  const diffY = e.changedTouches[0].screenY - startY;
  const ratioX = Math.abs(diffX / diffY);
  const ratioY = Math.abs(diffY / diffX);
  const absDiff = Math.abs(ratioX > ratioY ? diffX : diffY);

  // Ignore small movements.
  if (absDiff < 30) {
    return;
  }

  if (ratioX > ratioY) {
    if (diffX >= 0) {
      console.log('right swipe');
    } else {
      console.log('left swipe');
    }
  } else {
    if (diffY >= 0) {
      console.log('down swipe');
    } else {
      console.log('up swipe');
    }
  }
}

hello, I tried to use your answer and make simple func for that. Also want to make it for only swipe left. Any help?
I tried this and error.

function swipe(e) {
handleTouchStart(e);
handleTouchEnd(e);
}
let e = document.querySelector('.nbr');

swipe(e);

I have a quite lengthy solution that handles touchstart, touchmove, and touchend events alone. ~100 lines of code (minus comments).
This solution also returns the amount of pixels swiped, useful for creating a carousel or a swipeable component.

The code is below, you can modify it and get rid of what you don't need.

//to check that it's the right direction.
    const log = x => console.log(x)

class RootSwipeable {
    //offset is amount of pixels swiped to be considered a direction.
    //else multiple directions might trigger at once.
    constructor({ offset }) { 
        this.offset = offset
        this.previous = { x: null, y: null } 
    }

    updatePrevious(e) {
        this.previous.x =  e.changedTouches[0].screenX
        this.previous.y =  e.changedTouches[0].screenY
    }

    init(e) {
         !this.previous.x && !this.previous.y 
             && this.updatePrevious(e);
    }

    handleGesture(e, {
      onLeft = () => { }, 
      onRight = () => { },
      onUp = () => { }, 
      onDown = () => { } }) 
  {
    let screenX =  e.changedTouches[0].screenX,
         screenY =  e.changedTouches[0].screenY;

    if (this.previous.x + this.offset < screenX) {
        log('right')
        this.updatePrevious(e)
        onRight()
        return
    }
    if (this.previous.x - this.offset > screenX) {
        log('left')
        this.updatePrevious(e)
        onLeft()
        return
    }
    if (this.previous.y + this.offset < screenY) {
        log('down')
        this.updatePrevious(e)
        onDown()
        return
    }
    if (this.previous.y - this.offset > screenY) {
        log('up')
        this.updatePrevious(e)
        onUp()
        return
    }
  }

  kill() { this.previous = { x: null, y: null } }
}

//edited "c7x43t's" code above...
//main method.
export default class Swipeable {
    constructor({ offset }) {
        this.root = new RootSwipeable({ offset })
        this.pageWidth = window.innerWidth || document.body.clientWidth
        this.threshold = Math.max(1, Math.floor(0.01 * (this.pageWidth)))
        this.touchstart = { x: 0, y: 0 }
        this.touchend = { x: 0, y: 0 }
        this.limit = Math.tan(45 * 1.5 / 180 * Math.PI)
    }

    touchStart(e) {
        root.init(e)
        this.touchstart.x = e.changedTouches[0].screenX
        this.touchstart.y = e.changedTouches[0].screenY
    }
    touchMove(e, {
        onLeft = () => { }, 
        onRight = () => { },
        onUp = () => { },
        onDown = () => { }
    }) {
        this.touchend.x = e.changedTouches[0].screenX;
        this.touchend.y = e.changedTouches[0].screenY;
        this.handleGesture(e, { onLeft, onRight, onUp, onDown })
    }

    handleGesture(e, { onLeft, onRight, onUp, onDown }) {
        let x = this.touchend.x - this.touchstart.x,
        y = this.touchend.y - this.touchstart.y;
    
        if (Math.abs(x) > this.threshold || Math.abs(y) > this.threshold) {
   
            root.handleGestures(e, {
               onUp: () => onUp(e, y),
               onRight: () => onRight(e, x),
               onDown: () => onDown(e, y),
               onLeft: () => onLeft(e, x)
            })

            //root.handleGestures() is the initial root class above.//
        }
    }

    touchEnd() {
        root.kill()
        this.touchstart = { x: 0, y: 0 }
        this.touchend = { x: 0, y: 0 }
    }
}

The module above will then be used as so

import Swipeable from '@file_location'

//offset is preferably a number >= 2 && <= 10.
const swipeable = new Swipeable({ offset: 2 })

//example component: carousel//
document.querySelector('.carousel').addEventListener('touchstart', e => swipeable.touchStart(e))
document.querySelector('.carousel').addEventListener('touchmove', e => {
    swipeable.touchMove(e, { onUp: (e, x) => console.log(e, x + 'px swiped') })
})
document.querySelector('.carousel').addEventListener('touchend', e => swipeable.touchEnd(e))

Works great, thanks!

@tryhardest

This is starting to look like one of the leading script threads on vanillaJS touch events. Seems like Hammer, Zing and Interactjs (pointer events) libs (interact excluded) are maybe become a bit obsolete except for drag, drop, and pointer support. Does anyone have any flushed out changes they have made since (as the thread goes back a few years)? Would be cool to keep this thread up to date with any changes or learnings. Anyone using this extensively with event listeners on touchMove? @evrenakar @tlacaelelrl @hperrin

Despite not doing any work on it in a couple years, I still do maintain and use my version with the additional features I mentioned:
https://github.com/sciactive/tinygesture