detect-pointer-events

Detect Pointer Events

Detect if the browser supports the pointer events api.

Live detection test

Exports a reference to a singleton object (a micro state machine with an update function) with its state set to if the browser supports the pointer events api, (and if so does the api require a prefix, is it running on a touch device, and how many touch points does the device have), as well as an update() function which re-runs the tests and updates the object's state. There is also a prefix(value) function which will return the value and only add a prefix to it if it's required.

Note that detect-pointer-events is one of the micro state machines used by detect-it to determine if a device is mouseOnly, touchOnly, or hybrid.

For more information on the pointer events api, please see MDN's Pointer Events, or the W3C Pointer Events specification.

detectPointerEvents micro state machine

const detectPointerEvents = {
  hasApi: boolean,
  requiresPrefix: boolean,
  hasTouch: boolean,
  maxTouchPoints: whole number,

  // re-run all the detection tests and update state
  update() {...},

  // prefix the passed in value only if requiresPrefix === true
  prefix(value) {...},
}

Installing detect-pointer-events

$ npm install detect-pointer-events

Using detect-pointer-events

import detectPointerEvents from 'detect-pointer-events';

// using the state
detectPointerEvents.hasApi === true; // pointer events api is present in the browser
detectPointerEvents.requiresPrefix === true; // use of pointer events requires the Microsoft prefix
detectPointerEvents.hasTouch === true; // pointer events running on a touch capable device
detectPointerEvents.maxTouchPoints; // maximum number of touch points supported by the device

// updating the state - most apps won't need to use this at all
detectPointerEvents.update();

// prefixing pointer events
detectPointerEvents.prefix(value) // returns the value and only adds the prefix if requiresPrefix

// for example, this will add an event listener for 'MSPointerDown' if requiresPrefix === true,
// otherwise it will add an event listener for 'pointerdown'
element.addEventListener(detectPointerEvents.prefix('pointerdown'), function...)

/*
 * note that in the case of a browser that doesn't support pointer events,
 * including when using a legacy computer and browser, the default state will be:
 */
const detectPointerEvents = {
  hasApi: false,
  requiresPrefix: undefined,
  hasTouch: undefined,
  maxTouchPoints: undefined,
}

For reference, here is the pointer events prefix map used by the prefix() function.

Note that the update() function is run once at the time of import to set the object's initial state, and generally doesn't need to be run again. If it doesn't have access to the window, then the state will be undefined (detect-pointer-events will not throw an error), and you will have to call the update() function manually at a later time to update its state.

Part of the detect-it family

• detect-it
  • detect-hover
  • detect-pointer
  • detect-touch-events
  • detect-pointer-events
  • detect-passive-events