point

Unified, Observable Touch and Mouse Events

point

Use observable (well, actually Observ now) to monitor mouse and touch events.

First bind to the element you wish to capture data for. In this case let's capture data at the document level:

var point = require('point')(document);

Now to receive the pointer events simply pass point a function that will process the data:

point(function(args) {
  console.log(args);
});

The event data is passed to the function as a 4 element array:

[ pageX, pageY, data, originalEvent ]

At this stage, the data object args[2] simply tells you the type of the pointer event:

{ type: 'start' }

Possible values:

  • start
  • move
  • end

Using this module in conjunction with a pull-stream and pull-observable it is possible to replicate the function of a library that I wrote a few years ago called interact. Interact was designed to capture bound events and send them to a message bus Using eve:

var pull = require('pull-stream');
var observe = require('pull-observable');
var point = require('point');
var eve = require('eve');
 
eve.on('pointer.*', function(xy) {
  console.log('captured: ' + eve.nt() + ' @ ', x, y);
});
 
pull(
  observe(point(document)),
  pull.drain(function(args) {
    var type = (args[2] || {}).type;
 
    eve.apply(null, ['pointer.' + type, args[3]].concat(args.slice(0, 2)));
  })
);
 
 

Create a new Observable that will be updated in response to pointer movement on the specified target.

The following options can be provided to tweak behaviour:

  • over - capture mouse over events in addition to mouse move events
  • preventDefault - whether the default event behaviour should be prevented in the browser event listeners.

Copyright (c) 2015 Damon Oehlman damon.oehlman@gmail.com

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