delegate-events/index.js

Event delegation component

/**
 * Module dependencies.
 */

var closest = require('closest')
  , event = require('component-event');

/**
 * Delegate event `type` to `selector`
 * and invoke `fn(e)`. A callback function
 * is returned which may be passed to `.unbind()`.
 *
 * @param {Element} el
 * @param {String} selector
 * @param {String} type
 * @param {Function} fn
 * @param {Boolean} capture
 * @return {Function}
 * @api public
 */

// Some events don't bubble, so we want to bind to the capture phase instead
// when delegating.
var forceCaptureEvents = ['focus', 'blur'];

exports.bind = function(el, selector, type, fn, capture){
  if (forceCaptureEvents.indexOf(type) !== -1) capture = true;

  return event.bind(el, type, function(e){
    var target = e.target || e.srcElement;
    e.delegateTarget = closest(target, selector, true, el);
    if (e.delegateTarget) fn.call(el, e);
  }, capture);
};

/**
 * Unbind event `type`'s callback `fn`.
 *
 * @param {Element} el
 * @param {String} type
 * @param {Function} fn
 * @param {Boolean} capture
 * @api public
 */

exports.unbind = function(el, type, fn, capture){
  if (forceCaptureEvents.indexOf(type) !== -1) capture = true;

  event.unbind(el, type, fn, capture);
};