[patch/cla] dijit.getEnclosingWidget optimization

[Les]

Cache node.getAttribute("widgetId") in a local variable to improve loop performance.

dijit.getEnclosingWidget = function(/* DOMNode */ node) {
    while(node) {
        var widgetId = node.getAttribute && node.getAttribute("widgetId");
        if(widgetId) {
            return dijit.registry.byId(widgetId);
        }
        node = node.parentNode;
    }
    return null;
};

Test setup 1.) ​http://archive.dojotoolkit.org/nightly/dojotoolkit/dijit/tests/test_Menu.html#

2.) Run

var getEnclosingWidget = function (/* DOMNode */ node) {
    while(node) {
        var widgetId = node.getAttribute && node.getAttribute("widgetId");
        if(widgetId) {
            return dijit.registry.byId(widgetId);
        }
        node = node.parentNode;
    }
    return null;
};

var id = "dijit_MenuItem_42";
var node = dojo.byId(id);

console.time('old');
for (var i = 0; i < 100000; i++) {
    dijit.getEnclosingWidget(node);
}
console.timeEnd('old');

console.time('new');
for (var i = 0; i < 100000; i++) {
    getEnclosingWidget(node);
}
console.timeEnd('new');

Test results:

Safari 4 (Win): 409ms --> 195ms
FF 3.5: 740ms --> 473ms
IE 6: 5312ms --> 3219ms
Chrome 4: 298ms --> 109ms
IE 8: 1687ms --> 1063ms (test on another PC)

[bill]

Sure, make sense.

[bill]

(In [20107]) Dijit performance optimizations from Les Szklanny (CLA on file), thanks! Fixes #9885, #9875, #9879, refs #9131. !strict

[bill]

seems like these aren't really enhancements from the users' point of view, labeling as tasks instead