SOURCE CODE: Uize.Dom.Event (view docs)

/*______________
|       ______  |   U I Z E    J A V A S C R I P T    F R A M E W O R K
|     /      /  |   ---------------------------------------------------
|    /    O /   |    MODULE : Uize.Dom.Event Package
|   /    / /    |
|  /    / /  /| |    ONLINE : http://www.uize.com
| /____/ /__/_| | COPYRIGHT : (c)2009-2016 UIZE
|          /___ |   LICENSE : Available under MIT License or GNU General Public License
|_______________|             http://www.uize.com/license.html
*/

/*?
  Introduction
    The =Uize.Dom.Event= package provides convenient methods for abstracting differences between the DOM node event systems of different browsers.

    *DEVELOPERS:* `Chris van Rensburg`
*/

/* Module Meta Data
  type: Package
  importance: 6
  codeCompleteness: 80
  docCompleteness: 100
*/

Uize.module ({
  name:'Uize.Dom.Event',
  builder:function () {
    'use strict';

    /*** Utility Functions ***/
      function _preventDefault () {
        this.returnValue = false;
        /* NOTES:
          - "preventDefault" is the DOM standard, "returnValue" is older IE's proprietary feature
          - this approach does not work for the keydown event in Safari (use the keypress event, instead)
        */
      }

      function _stopPropagation () {
        this.cancelBubble = true;
        /* NOTES:
          - "stopPropagation" is the DOM standard, "cancelBubble" is older IE's proprietary feature
        */
      }

    /*** Public Static Methods ***/
      var _package = Uize.copyInto (
        function (_event) {return _event || event},
        {
          abort:function (_event) {
            _package.preventDefault (_event = _package (_event));
            _package.stopPropagation (_event);
            /*?
              Static Methods
                Uize.Dom.Event.abort
                  Aborts the specified DOM event, preventing the browser's default action for that event from taking place, and also preventing the event from being propagated.

                  SYNTAX
                  ...................................
                  Uize.Dom.Event.abort (domEventOBJ);
                  ...................................

                  Calling this method has the same effect as calling both the =Uize.Dom.Event.preventDefault= and =Uize.Dom.Event.stopPropagation= static methods for the specified DOM event.

                  NOTES
                  - see the related =Uize.Dom.Event.preventDefault= and =Uize.Dom.Event.stopPropagation= static methods
            */
          },

          charCode:function (_event) {
            _event = _package (_event);
            if (_event.ctrlKey || _event.altKey || _event.which < 1)
              return 0
            ;
            return 'charCode' in _event ? _event.charCode : _package.keyCode (_event);

            /* for keydown / keyup
              var _keyCodeToCharCodeRemap = {
                192:'`', 1192:'~', 1049:'!', 1050:'@', 1051:'#', 1052:'$', 1053:'%', 1054:'^', 1055:'&', 1056:'*', 1057:'(', 1048:')', 109:'-', 1109:'_', 107:'=', 1107:'+', 219:'[', 1219:'{', 221:']', 1221:'}', 220:'\\', 1220:'|', 59:';', 1059:':', 222:'\'', 1222:'"', 226:'\\', 1226:'|', 188:',', 1188:'<', 190:'.', 1190:'>', 191:'/', 1191:'?',

                // numerical keypad
                  111:'/', 1111:'/', 106:'*', 1106:'*', 109:'-', 110:'.', 1110:'.'
              };
              function _getKeyEventCharCode (_domEvent) {
                var
                  _keyCode = 'which' in _domEvent ? _domEvent.which : _domEvent.keyCode,
                  _result = _keyCode
                ;
                if (_result > 64 && _result < 91) { // 65-90 are a-z/A-Z
                  if (!_domEvent.shiftKey) _result += 32;
                } else if (_result > 95 && _result < 106) { // 96-105 are 0-9 on numerical keypad
                  _result -= 48;
                } else if (_result > 111 && _result < 123) { // 112-123 are F1-F12 (the function keys)
                  _result = 0;
                } else {
                  var _remappedChar = _keyCodeToCharCodeRemap [(_domEvent.shiftKey && 1000) + _result];
                  if (_remappedChar) _result = _remappedChar.charCodeAt (0);
                }
                page.setNodeValue ('test',_keyCode + '(Shift: ' + _domEvent.shiftKey + ') -> ' + _result + ' = ' + String.fromCharCode (_result));
                return _result;
              }
            */
            /*?
              Static Methods
                Uize.Dom.Event.charCode
                  Returns an integer, indicating the character code of the key being pressed in the =keypress= keyboard event.

                  SYNTAX
                  ....................................................
                  charCodeINT = Uize.Dom.Event.charCode (domEventOBJ);
                  ....................................................

                  In order to get the actual character for the key that is being pressed, you can use the =String.fromCharCode= method, as in...

                  .........................................................................
                  keyCharSTR = String.fromCharCode (Uize.Dom.Event.charCode (domEventOBJ));
                  .........................................................................

                  NOTES
                  - this method is applicable only to the =keypress= event and is not guaranteed to work reliably with the =keydown= and =keyup= events
                  - if the key being pressed is a special key that would not produce a character (such as one of the cursor arrow keys), then this method will return the value =0=
                  - see the related =Uize.Dom.Event.keyCode= static method
                  - this method does not modify the DOM event object
            */
          },

          fix:function (_event) {
            _event = _package (_event);

            for (var _propertyName in {target:1, relatedTarget:1, charCode:1, keyCode:1})
              _propertyName in _event || (_event [_propertyName] = _package [_propertyName] (_event))
            ;
            _event.preventDefault || (_event.preventDefault = _preventDefault);
            _event.stopPropagation || (_event.stopPropagation = _stopPropagation);

            return _event;
            /*?
              Static Methods
                Uize.Dom.Event.fix
                  Performs some fixes on the specified event object by extending it with DOM standard event object methods and properties, as necessary.

                  SYNTAX
                  ...............................................
                  domEventOBJ = Uize.Dom.Event.fix (domEventOBJ);
                  ...............................................

                  This method abstracts the difference between Microsoft Internet Explorer, which supports proprietary properties on the event object, and other browsers that support the DOM standard methods and properties. Among other things, this method will extend the specified DOM event object with the =preventDefault= and =stopPropagation= methods, and the =charCode=, =relatedTarget=, and =target= properties, as necessary.

                  NOTES
                  - this method may modify the DOM event object
            */
          },

          keyCode:function (_event) {
            return 'which' in (_event = _package (_event)) ? _event.which : _event.keyCode;
            /*?
              Static Methods
                Uize.Dom.Event.keyCode
                  Returns an integer, indicating the key code of the key being pressed in the =keydown= or =keyup= keyboard event.

                  SYNTAX
                  ..................................................
                  keyCodeINT = Uize.Dom.Event.keyCode (domEventOBJ);
                  ..................................................

                  Not a Character Code
                    It's important to point out that the key code for a keyboard event does not correspond in a predictable or meaningful way to a character that might be produced when a key is pressed in a focused text input field.

                    For example, the key code when "Shift-a" is pressed is the same as when just "a" is pressed, even though the former would produce a capital "A" while the latter would produce a lowercase "a". The key code =65=, in this case, merely identifies the "A" key on the keyboard. In other cases, certain keys will produce key codes that don't meaningfully map to characters in the ASCII character set. For example, the key code for the down arrow key is =40=, and =40= is the ASCII character code for the "(" (open parenthesis) character - not a meaningful mapping at all.

                  Testing for Certain Keys
                    As a convenience, a number of static methods are provided in this module to make it easier to detect certain keys without having to remember the key codes.

                    An example is the =Uize.Dom.Event.isKeyEnter= method, which tests if the key being pressed down or released is the enter key. Other such methods include: =Uize.Dom.Event.isKeyEscape=, =Uize.Dom.Event.isKeyDownArrow=, =Uize.Dom.Event.isKeyInsert=, =Uize.Dom.Event.isKeyTab=, etc.

                  NOTES
                  - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
                  - see the related =Uize.Dom.Event.charCode= static method
                  - this method does not modify the DOM event object
            */
          },

          preventDefault:function (_event) {
            (_event = _package (_event)).preventDefault ? _event.preventDefault () : _preventDefault.call (_event);
            /*?
              Static Methods
                Uize.Dom.Event.preventDefault
                  Prevents the browser's default action for the specified event from being performed.

                  SYNTAX
                  ............................................
                  Uize.Dom.Event.preventDefault (domEventOBJ);
                  ............................................

                  This method abstracts the difference between Microsoft Internet Explorer, which supports the proprietary =returnValue= property on the event object, and other browsers that support the DOM standard =preventDefault= method of the event object.

                  NOTES
                  - see the related =Uize.Dom.Event.abort= and =Uize.Dom.Event.stopPropagation= static methods
                  - this method may modify the DOM event object
            */
          },

          relatedTarget:function (_event) {
            return (
              'relatedTarget' in (_event = _package (_event))
                ? _event.relatedTarget
                : (_event.type == 'mouseout' ? _event.toElement : _event.fromElement)
            );
            /* NOTES:
              - "relatedTarget" is the DOM standard, "toElement" and "fromElement" are IE's proprietary features
            */
            /*?
              Static Methods
                Uize.Dom.Event.relatedTarget
                  Returns a reference to a DOM node, identifying the secondary target for a =mouseover= or =mouseout= event.

                  SYNTAX
                  .....................................................................
                  relatedTargetDomNodeOBJ = Uize.Dom.Event.relatedTarget (domEventOBJ);
                  .....................................................................

                  This method is only applicable to / meaningful for the =mouseover= and =mouseout= mouse events, where the value returned for a =mouseover= event will be the DOM node that the mouse exited in order to enter the new node, and where the value returned for a =mouseout= event will be the DOM node that the mouse is entering as it exits the current node.

                  ..................................................................................................
                  << table >>

                  title: Target and Related Target
                  data
                  :| domEvent.name | Uize.Dom.Event.target (domEvent) | Uize.Dom.Event.relatedTarget (domEvent)  |
                  :|  'mouseover'  |  the node that mouse is entering  |    the node that mouse is leaving         |
                  :|  'mouseout'   |  the node that mouse is leaving   |    the node that mouse is entering        |
                  ..................................................................................................

                  This method abstracts the difference between Microsoft Internet Explorer, which supports the proprietary =fromElement= and =toElement= properties on the event object, and other browsers that support the DOM standard =relatedTarget= property.

                  NOTES
                  - this method is only applicable to the =mouseover= and =mouseout= mouse events
                  - see the related =Uize.Dom.Event.target= static method
                  - this method does not modify the DOM event object
            */
          },

          stopPropagation:function (_event) {
            (_event = _package (_event)).stopPropagation ? _event.stopPropagation () : _stopPropagation.call (_event);
            /*?
              Static Methods
                Uize.Dom.Event.stopPropagation
                  Stops the propagation of the specified DOM event to other nodes in the DOM.

                  SYNTAX
                  .............................................
                  Uize.Dom.Event.stopPropagation (domEventOBJ);
                  .............................................

                  Using this method for an event will prevent the event from being propagated / bubbled up to nodes that are up the parentNode chain for the node that is the target of the event. Consider the following example...

                  EXAMPLE
                  ..........................................................
                  Uize.Dom.Basics.wire (
                    myNode,
                    'click',
                    function (domEvent) {
                      Uize.Dom.Event.stopPropagation (domEvent);
                      alert ('You should see this message.');
                    }
                  );
                  Uize.Dom.Basics.wire (
                    myNode.parentNode,
                    'click',
                    function (domEvent) {
                      if (Uize.Dom.Event.target (domEvent) == myNode) {
                        alert ('You should NOT be seeing this message!');
                      }
                    }
                  );
                  ..........................................................

                  In the above example, handlers are being wired for the =click= event of the node =myNode= and its parent node. Under normal circumstances, the user clicking on =myNode= would cause the =click= event to be fired first for that node and then for its parent node as the event is bubbled. In this case, however, the handler for =click= on =myNode= is using the =Uize.Dom.Event.stopPropagation= method to cancel the bubbling of the event up to the parent node. Therefore, clicking on the node =myNode= should never produce an alert with the message "You should NOT be seeing this message!".

                  This method abstracts the difference between Microsoft Internet Explorer, which supports the proprietary =cancelBubble= property on the event object, and other browsers that support the DOM standard =stopPropagation= method of the event object.

                  NOTES
                  - this method may modify the DOM event object
                  - see the related =Uize.Dom.Event.abort= and =Uize.Dom.Event.preventDefault= static methods
            */
          },

          target:function (_event) {
            return (_event = _package (_event)).target || _event.srcElement;
            /* NOTES:
              - "target" is the DOM standard, "srcElement" is IE's proprietary feature
            */
            /*?
              Static Methods
                Uize.Dom.Event.target
                  Returns a reference to a DOM node, being the node from which the specified DOM event was dispatched.

                  SYNTAX
                  .......................................................
                  targetDomNodeOBJ = Uize.Dom.Event.target (domEventOBJ);
                  .......................................................

                  This method abstracts the difference between Microsoft Internet Explorer, which supports the proprietary =srcElement= property on the event object, and other browsers that support the DOM standard =target= property.

                  NOTES
                  - see the related =Uize.Dom.Event.relatedTarget= static method
                  - this method does not modify the DOM event object
            */
          }
        }
      );

      Uize.map (
        {
          Backspace:8,Delete:46,Insert:45,
          Enter:13,Escape:27,
          Space:32,Tab:9,
          PageUp:33,PageDown:34,End:35,Home:36,
          LeftArrow:37,RightArrow:39,UpArrow:38,DownArrow:40
        },
        function (_keyCode,_keyName) {
          _package ['isKey' + _keyName] = function (_event) {return _package.keyCode (_event) == _keyCode};
        }
        /*?
          Static Methods
            Uize.Dom.Event.isKeyBackspace
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the backspace key.

              SYNTAX
              .................................................................
              isKeyBackspaceBOOL = Uize.Dom.Event.isKeyBackspace (domEventOBJ);
              .................................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyDownArrow
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the down arrow key.

              SYNTAX
              .................................................................
              isKeyDownArrowBOOL = Uize.Dom.Event.isKeyDownArrow (domEventOBJ);
              .................................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyDelete
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the delete key.

              SYNTAX
              ...........................................................
              isKeyDeleteBOOL = Uize.Dom.Event.isKeyDelete (domEventOBJ);
              ...........................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyEnd
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the end key.

              SYNTAX
              .....................................................
              isKeyEndBOOL = Uize.Dom.Event.isKeyEnd (domEventOBJ);
              .....................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyEnter
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the home key.

              SYNTAX
              .........................................................
              isKeyEnterBOOL = Uize.Dom.Event.isKeyEnter (domEventOBJ);
              .........................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyEscape
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the escape key.

              SYNTAX
              ...........................................................
              isKeyEscapeBOOL = Uize.Dom.Event.isKeyEscape (domEventOBJ);
              ...........................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyHome
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the home key.

              SYNTAX
              .......................................................
              isKeyHomeBOOL = Uize.Dom.Event.isKeyHome (domEventOBJ);
              .......................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyInsert
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the insert key.

              SYNTAX
              ...........................................................
              isKeyInsertBOOL = Uize.Dom.Event.isKeyInsert (domEventOBJ);
              ...........................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyLeftArrow
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the left arrow key.

              SYNTAX
              .................................................................
              isKeyLeftArrowBOOL = Uize.Dom.Event.isKeyLeftArrow (domEventOBJ);
              .................................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyPageDown
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the page down key.

              SYNTAX
              ...............................................................
              isKeyPageDownBOOL = Uize.Dom.Event.isKeyPageDown (domEventOBJ);
              ...............................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyPageUp
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the page up key.

              SYNTAX
              ...........................................................
              isKeyPageUpBOOL = Uize.Dom.Event.isKeyPageUp (domEventOBJ);
              ...........................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyRightArrow
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the right arrow key.

              SYNTAX
              ...................................................................
              isKeyRightArrowBOOL = Uize.Dom.Event.isKeyRightArrow (domEventOBJ);
              ...................................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeySpace
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the space key.

              SYNTAX
              .........................................................
              isKeySpaceBOOL = Uize.Dom.Event.isKeySpace (domEventOBJ);
              .........................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyTab
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the tab key.

              SYNTAX
              .....................................................
              isKeyTabBOOL = Uize.Dom.Event.isKeyTab (domEventOBJ);
              .....................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object

            Uize.Dom.Event.isKeyUpArrow
              Returns a boolean, indicating whether or not the key being pressed in the keyboard event is the up arrow key.

              SYNTAX
              .............................................................
              isKeyUpArrowBOOL = Uize.Dom.Event.isKeyUpArrow (domEventOBJ);
              .............................................................

              NOTES
              - this method is applicable to the =keydown= and =keyup= events and is not guaranteed to work reliably with the =keypress= event
              - this method does not modify the DOM event object
        */
      );

    return _package;
  }
});