swipe-listener

Swipe-Listener

Zero-dependency, minimal swipe-gesture listener for the web.

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Demo

What

Swipe-listener is a very minimal library that allows listening for swipe gesture on literally any DOM element. Once invoked with a DOM element, simply listen for swipe event and determine the direction with the directions object.

Example Code

var container = document.querySelector('#container');
var listener = SwipeListener(container);
container.addEventListener('swipe', function (e) {
  var directions = e.detail.directions;
  var x = e.detail.x;
  var y = e.detail.y;

  if (directions.left) {
    console.log('Swiped left.');
  }

  if (directions.right) {
    console.log('Swiped right.');
  }

  if (directions.top) {
    console.log('Swiped top.');
  }

  if (directions.bottom) {
    console.log('Swiped bottom.');
  }

  if (directions.top && directions.right) {
    console.log('Swiped top-right.');
  }

  if (directions.top && directions.left) {
    console.log('Swiped top-left.');
  }

  if (directions.bottom && directions.right) {
    console.log('Swiped bottom-right.');
  }

  if (directions.bottom && directions.left) {
    console.log('Swiped bottom-left.');
  }

  console.log('Started horizontally at', x[0], 'and ended at', x[1]);
  console.log('Started vertically at', y[0], 'and ended at', y[1]);
});

Installation

Browser

<script src="path/to/swipe-listener.min.js" type="text/javascript"></script>
<script>
  var container = document.querySelector('#container');
  var listener = SwipeListener(container);
  container.addEventListener('swipe', function (e) {
    console.log(e.detail);
  });
</script>

Swipe-listener is also available from unpkg: https://unpkg.com/swipe-listener@1.2.0/dist/swipe-listener.min.js

Installing using NPM

Install from NPM using npm i --save swipe-listener, then

import SwipeListener from 'swipe-listener';

OR

const SwipeListener = require('swipe-listener');

API

SwipeListener(element, options)

• element DOM Element on which you want to enable swipe gesture tracking. This is the element on which you will be attacking the swipe event listener.
• options [Optional] Configuration options (see below)

Listen for swipe event on the element passed. Access details using event.detail. For example, directions can be accessed using event.detail.directions. See events for more events.

Data passed to event.detail:

• directions (Object)
  • top (Boolean) Signifies a top-swipe.
  • right (Boolean) Signifies a right-swipe.
  • bottom (Boolean) Signifies a bottom-swipe.
  • left (Boolean) Signifies a left-swipe.
• x (Array) Array containing two elements: starting and ending x-coords.
• y (Array) Array containing two elements: starting and ending y-coords.
• touch (Boolean) Whether or not TouchEvent was used for this particular event.

Note that multiple directions can be true at one. In case of a top-left swipe, directions.top and directions.left will both be true.

Options

Key	Description	Default value
minHorizontal	Minimum number of horizontal pixels travelled for the gesture to be considered as a left or right swipe.	10
minVertical	Minimum number of vertical pixels travelled for the gesture to be considered as a top or bottom swipe.	10
deltaHorizontal	Maximum difference between the rightmost pixel (right-swipe) or the leftmost pixel (left-swipe) travelled to and the pixel at which the gesture is released.	3
deltaVertical	Maximum difference between the bottommost pixel (bottom-swipe) or the topmost pixel (top-swipe) travelled to and the pixel at which the gesture is released.	5
preventScroll	Prevents page scrolling when swiping on the DOM element. Can also be specified as a function with the signature (event) => boolean	false
lockAxis	Enforces only one direction to be true instead of multiple. Selects the direction with the most travel. Is not enforced when the travel is equal. Example: for a top-left swipe, only one of top and left will be true instead of both.	true
touch	Whether to listen for swipes with touch events	true
mouse	Whether to listen for swipes with mouse events	true

.off()

Turns off the swipe-listener on a given element.

Usage:

var listener = SwipeListener(myElem);
listener.off();

Events

swipe - Emitted once a swipe is performed.

Emitted once a swipe is completed.

event.detail contains

key	type	description
directions	Object	Object containing top, left, bottom, right keys. The directions in which the swipe is performed are set to true.
x	Array	Array of two items: the starting x-coordinate and the ending x-coordinate.
y	Array	Array of two items: the starting y-coordinate and the ending y-coordinate.
touch	Boolean	Whether or not TouchEvent was used for this particular event.

swiping - Emitted while a swipe is being performed.

Emitted multiple times during a single swipe.

event.detail contains

key	type	description
x	Array	Array of two items: the starting x-coordinate and the ending x-coordinate.
y	Array	Array of two items: the starting y-coordinate and the ending y-coordinate.
touch	Boolean	Whether or not TouchEvent was used for this particular event.

swiperelease - Emitted once the swipe is released/completed.

Emitted at the end of the swipe.

event.detail contains

key	type	description
x	Array	Array of two items: the starting x-coordinate and the ending x-coordinate.
y	Array	Array of two items: the starting y-coordinate and the ending y-coordinate.
touch	Boolean	Whether or not TouchEvent was used for this particular event.

swipecancel - Emitted if the swipe-distance did not meet minimum travel-distance.

Emitted at the end of the swipe.

event.detail contains

key	type	description
x	Array	Array of two items: the starting x-coordinate and the ending x-coordinate.
y	Array	Array of two items: the starting y-coordinate and the ending y-coordinate.
touch	Boolean	Whether or not TouchEvent was used for this particular event.

Misc

• When lockAxis is false, swipes using the mouse might make multiple directions true even when the travel in a certain direction may not be much. You can work around this by setting lockAxis to true when the page is not being accessed from a touch-enabled device. Or, you can use event.detail.x and event.detail.y to calculate which direction has more travel and consider only that direction. Or, you can increase the values of minVertical and minHorizontal.
• TouchEvent is not supported in IE and Edge. Unless you have polyfilled it into the page and it's available as TouchEvent, swipes made using touch will not be detected as touch swipes.

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License

MIT License © Umang Galaiya

Changelog

1.3.0

• Allow preventScroll to be a function (#33)