tinygesture

Very small gesture recognizer for JavaScript. Swipe, pan, tap, doubletap, and longpress.

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TinyGesture.js
Very small gesture recognizer for JavaScript. Swipe, pan, tap, doubletap, and longpress.

Installation

npm install --save tinygesture

If you're upgrading from 1.0, the only breaking change in 2.0 is the location of the file. It's now in a "dist" folder, hence the major version change.

Usage

Constructor and Options

import TinyGesture from 'tinygesture';

// Options object is optional. These are the defaults.
const options = {
  // Used to calculate the threshold to consider a movement a swipe. it is
  // passed type of 'x' or 'y'.
  threshold: (type, self) =>
    Math.max(
      25,
      Math.floor(
        0.15 *
          (type === 'x'
            ? window.innerWidth || document.body.clientWidth
            : window.innerHeight || document.body.clientHeight)
      )
    ),
  // Minimum velocity the gesture must be moving when the gesture ends to be
  // considered a swipe.
  velocityThreshold: 10,
  // Used to calculate the distance threshold to ignore the gestures velocity
  // and always consider it a swipe.
  disregardVelocityThreshold: (type, self) =>
    Math.floor(0.5 * (type === 'x' ? self.element.clientWidth : self.element.clientHeight)),
  // Point at which the pointer moved too much to consider it a tap or longpress
  // gesture.
  pressThreshold: 8,
  // If true, swiping in a diagonal direction will fire both a horizontal and a
  // vertical swipe.
  // If false, whichever direction the pointer moved more will be the only swipe
  // fired.
  diagonalSwipes: false,
  // The degree limit to consider a swipe when diagonalSwipes is true.
  diagonalLimit: Math.tan(((45 * 1.5) / 180) * Math.PI),
  // Listen to mouse events in addition to touch events. (For desktop support.)
  mouseSupport: true,
};

const target = document.getElementById('target');
const gesture = new TinyGesture(target, options);

Listening to Gesture Events

gesture.on('panstart', (event) => {
  // Always the original mouse or touch event.
  // This service uses passive listeners, so you can't call
  // event.preventDefault() on any of the events.
  event;
  // The (screen) x coordinate of the start of the gesture.
  gesture.touchStartX;
  // The (screen) y coordinate of the start of the gesture.
  gesture.touchStartY;
});
gesture.on('panmove', (event) => {
  // Everything from panstart, and...

  // The amount the gesture has moved in the x direction.
  gesture.touchMoveX;
  // The amount the gesture has moved in the y direction.
  gesture.touchMoveY;
  // The instantaneous velocity in the x direction.
  gesture.velocityX;
  // The instantaneous velocity in the y direction.
  gesture.velocityY;
  // Boolean, whether the gesture has passed the swiping threshold in the x
  // direction.
  gesture.swipingHorizontal;
  // Boolean, whether the gesture has passed the swiping threshold in the y
  // direction.
  gesture.swipingVertical;
  // Which direction the gesture has moved most. Prefixed with 'pre-' if the
  // gesture hasn't passed the corresponding threshold.
  // One of: ['horizontal', 'vertical', 'pre-horizontal', 'pre-vertical']
  gesture.swipingDirection;
  // To tell if the gesture is a left swipe, you can do something like this:
  if (gesture.swipingDirection === 'horizontal' && gesture.touchMoveX < 0) {
    alert('You are currently swiping left.');
  }
});
gesture.on('panend', (event) => {
  // Everything from panstart and panmove, and...

  // The (screen) x coordinate of the end of the gesture.
  gesture.touchEndX;
  // The (screen) y coordinate of the end of the gesture.
  gesture.touchEndY;

  // Swipe events are fired depending on the touch end coordinates, so
  // properties like swipingDirection may be incorrect at this point, since
  // they're based on the last touch move coordinates.
});

gesture.on('swiperight', (event) => {
  // The gesture was a right swipe.

  // This will always be true for a right swipe.
  gesture.swipedHorizontal;
  // This will be true if diagonalSwipes is on and the gesture was diagonal
  // enough to also be a vertical swipe.
  gesture.swipedVertical;
});
gesture.on('swipeleft', (event) => {
  // The gesture was a left swipe.

  // This will always be true for a left swipe.
  gesture.swipedHorizontal;
  // This will be true if diagonalSwipes is on and the gesture was diagonal
  // enough to also be a vertical swipe.
  gesture.swipedVertical;
});
gesture.on('swipeup', (event) => {
  // The gesture was an upward swipe.

  // This will be true if diagonalSwipes is on and the gesture was diagonal
  // enough to also be a horizontal swipe.
  gesture.swipedHorizontal;
  // This will always be true for an upward swipe.
  gesture.swipedVertical;
});
gesture.on('swipedown', (event) => {
  // The gesture was a downward swipe.

  // This will be true if diagonalSwipes is on and the gesture was diagonal
  // enough to also be a horizontal swipe.
  gesture.swipedHorizontal;
  // This will always be true for a downward swipe.
  gesture.swipedVertical;
});

gesture.on('tap', (event) => {
  // The gesture was a tap. Keep in mind, it may have also been a long press.
});

gesture.on('doubletap', (event) => {
  // The gesture was a double tap. The 'tap' event will also have been fired on
  // the first tap.
});

gesture.on('longpress', (event) => {
  // The gesture is currently ongoing, and is now a long press.
});

Long Press without Tap

If you want to listen for both long press and tap, and distinguish between them, this is how to do it.
let pressed = false;

// Note: don't use the 'tap' event to detect when the user has finished a long
// press, because it doesn't always fire.
gesture.on('tap', () => {
  // If the user long pressed, don't run the tap handler. This event fires after
  // the user lifts their finger.
  if (pressed) {
    return;
  }
  // ... Your tap handling code here.
});

gesture.on('longpress', () => {
  // Indicate that this is a long press. This event fires before the user lifts
  // their finger.
  pressed = true;
  // ... Your long press ongoing handling code here.
});

gesture.on('panend', () => {
  // This is how you would detect when the user has finished a long press,
  // because 'panend' will always fire, even if the user has moved their finger
  // a little after 'longpress' has fired.
  if (pressed) {
    // ... Your long press finished handling code here.

    // Make sure to reset pressed after the current event loop.
    setTimeout(() => {
      pressed = false;
    }, 0);
  }
});

Un-listening to Gesture Events

// There are two ways to un-listen:
const callback = (event) => {};
const listener = gesture.on('tap', callback);
// First way.
listener.cancel();
// Second way.
gesture.off('tap', callback);

Firing Events

// If, for some reason, you want to programmatically fire all the listeners for
// some event:
gesture.fire('tap', eventObj);

Destruction

// When you're done, you can remove event listeners with:
gesture.destroy();

Credits

A lot of the initial ideas and code came from:
https://gist.github.com/SleepWalker/da5636b1abcbaff48c4d
and
https://github.com/uxitten/xwiper