Develop Reference

How to hook on library function (Golden Layout) and call additional methods

I'm using a library called Golden Layout, it has a function called destroy which will close all the application window, on window close or refesh
I need to add additional method to the destroy function. I need to removeall the localstorage aswell.
How do i do it ? Please help
Below is the plugin code.
lm.LayoutManager = function( config, container ) {
....
destroy: function() {
if( this.isInitialised === false ) {
return;
}
this._onUnload();
$( window ).off( 'resize', this._resizeFunction );
$( window ).off( 'unload beforeunload', this._unloadFunction );
this.root.callDownwards( '_$destroy', [], true );
this.root.contentItems = [];
this.tabDropPlaceholder.remove();
this.dropTargetIndicator.destroy();
this.transitionIndicator.destroy();
this.eventHub.destroy();
this._dragSources.forEach( function( dragSource ) {
dragSource._dragListener.destroy();
dragSource._element = null;
dragSource._itemConfig = null;
dragSource._dragListener = null;
} );
this._dragSources = [];
},
I can access the destroy method in the component like this
this.layout = new GoldenLayout(this.config, this.layoutElement.nativeElement);
this.layout.destroy();`
My code
#HostListener('window:beforeunload', ['$event'])
beforeunloadHandler(event) {
var originalDestroy = this.layout.destroy;
this.layout.destroy = function() {
// Call the original
originalDestroy.apply(this, arguments);
localStorage.clear();
};
}

Looking at the documentation, GoldenLayout offers an itemDestroyed event you could hook to do your custom cleanup. The description is:
Fired whenever an item gets destroyed.
If for some reason you can't, the general answer is that you can easily wrap the function:
var originalDestroy = this.layout.destroy;
this.layout.destroy = function() {
// Call the original
originalDestroy.apply(this, arguments);
// Do your additional work here
};
You may be able to do this for all instances if necessary by modifying GoldenLayout.prototype:
var originalDestroy = GoldenLayout.prototype.destroy;
GoldenLayout.prototype.destroy = function() {
// Call the original
originalDestroy.apply(this, arguments);
// Do your additional work here
};
Example:
// Stand-in for golden laout
function GoldenLayout() {
}
GoldenLayout.prototype.destroy = function() {
console.log("Standard functionality");
};
// Your override:
var originalDestroy = GoldenLayout.prototype.destroy;
GoldenLayout.prototype.destroy = function() {
// Call the original
originalDestroy.apply(this, arguments);
// Do your additional work here
console.log("Custom functionality");
};
// Use
var layout = new GoldenLayout();
layout.destroy();

Hooking into golden layout is the intended purpose for the events.
As briefly touched on by #T.J. Crowder, there is the itemDestroyed event which is called when an item in the layout is destroyed.
You can just listen for this event like such:
this.layout.on('itemDestroyed', function() {
localStorage.clear();
})
However, this event is called every time anything is destroyed, and propagates down the tree, even just by closing a tab. This means that if you call destroy on the layout root, you will get an event for every RowOrColumn, Stack and Component
I would recommend to check the item passed into the event and ignore if not the main window (root item)
this.layout.on('itemDestroyed', function(item) {
if (item.type === "root") {
localStorage.clear();
}
})

jQuery plugin instances variable with event handlers

I am writing my first jQuery plugin which is a tree browser. It shall first show the top level elements and on click go deeper and show (depending on level) the children in a different way.
I got this up and running already. But now I want to implement a "back" functionality and for this I need to store an array of clicked elements for each instance of the tree browser (if multiple are on the page).
I know that I can put instance private variables with "this." in the plugin.
But if I assign an event handler of the onClick on a topic, how do I get this instance private variable? $(this) is referencing the clicked element at this moment.
Could please anyone give me an advise or a link to a tutorial how to get this done?
I only found tutorial for instance specific variables without event handlers involved.
Any help is appreciated.
Thanks in advance.
UPDATE: I cleaned out the huge code generation and kept the logical structure. This is my code:
(function ($) {
$.fn.myTreeBrowser = function (options) {
clickedElements = [];
var defaults = {
textColor: "#000",
backgroundColor: "#fff",
fontSize: "1em",
titleAttribute: "Title",
idAttribute: "Id",
parentIdAttribute: "ParentId",
levelAttribute: "Level",
treeData: {}
};
var opts = $.extend({}, $.fn.myTreeBrowser.defaults, options);
function getTreeData(id) {
if (opts.data) {
$.ajax(opts.data, { async: false, data: { Id: id } }).success(function (resultdata) {
opts.treeData = resultdata;
});
}
}
function onClick() {
var id = $(this).attr('data-id');
var parentContainer = getParentContainer($(this));
handleOnClick(parentContainer, id);
}
function handleOnClick(parentContainer, id) {
if (opts.onTopicClicked) {
opts.onTopicClicked(id);
}
clickedElements.push(id);
if (id) {
var clickedElement = $.grep(opts.treeData, function (n, i) { return n[opts.idAttribute] === id })[0];
switch (clickedElement[opts.levelAttribute]) {
case 1:
renderLevel2(parentContainer, clickedElement);
break;
case 3:
renderLevel3(parentContainer, clickedElement);
break;
default:
debug('invalid level element clicked');
}
} else {
renderTopLevel(parentContainer);
}
}
function getParentContainer(elem) {
return $(elem).parents('div.myBrowserContainer').parents()[0];
}
function onBackButtonClick() {
clickedElements.pop(); // remove actual element to get the one before
var lastClickedId = clickedElements.pop();
var parentContainer = getParentContainer($(this));
handleOnClick(parentContainer, lastClickedId);
}
function renderLevel2(parentContainer, selectedElement) {
$(parentContainer).html('');
var browsercontainer = $('<div>').addClass('myBrowserContainer').appendTo(parentContainer);
//... rendering the div ...
// for example like this with a onClick handler
var div = $('<div>').attr('data-id', element[opts.idAttribute]).addClass('fct-bs-col-md-4 pexSubtopic').on('click', onClick).appendTo(subtopicList);
// ... rendering the tree
var backButton = $('<button>').addClass('btn btn-default').text('Back').appendTo(browsercontainer);
backButton.on('click', onBackButtonClick);
}
function renderLevel3(parentContainer, selectedElement) {
$(parentContainer).html('');
var browsercontainer = $('<div>').addClass('myBrowserContainer').appendTo(parentContainer);
//... rendering the div ...
// for example like this with a onClick handler
var div = $('<div>').attr('data-id', element[opts.idAttribute]).addClass('fct-bs-col-md-4 pexSubtopic').on('click', onClick).appendTo(subtopicList);
// ... rendering the tree
var backButton = $('<button>').addClass('btn btn-default').text('Back').appendTo(browsercontainer);
backButton.on('click', onBackButtonClick);
}
function renderTopLevel(parentContainer) {
parentContainer.html('');
var browsercontainer = $('<div>').addClass('fct-page-pa fct-bs-container-fluid pexPAs myBrowserContainer').appendTo(parentContainer);
// rendering the top level display
}
getTreeData();
//top level rendering! Lower levels are rendered in event handlers.
$(this).each(function () {
renderTopLevel($(this));
});
return this;
};
// Private function for debugging.
function debug(debugText) {
if (window.console && window.console.log) {
window.console.log(debugText);
}
};
}(jQuery));

Just use one more class variable and pass this to it. Usually I call it self. So var self = this; in constructor of your plugin Class and you are good to go.
Object oriented way:
function YourPlugin(){
var self = this;
}
YourPlugin.prototype = {
constructor: YourPlugin,
clickHandler: function(){
// here the self works
}
}
Check this Fiddle
Or simple way of passing data to eventHandler:
$( "#foo" ).bind( "click", {
self: this
}, function( event ) {
alert( event.data.self);
});

You could use the jQuery proxy function:
$(yourElement).bind("click", $.proxy(this.yourFunction, this));
You can then use this in yourFunction as the this in your plugin.

Scope of variable in DOJO when created from within function

In a DOJO widget there is code in the postCreate and destroy method to create/start and stop a timer like you can see below. Depending on the value in a drop down box the timer is started or stopped. This works fine so far.
postCreate: function() {
var deferred = this.own(<...some action...>)[0];
deferred.then(
lang.hitch(this, function(result) {
this.t = new dojox.timing.Timer(result.autoRefreshInterval * 1000);
this.t.onTick = lang.hitch(this, function() {
console.info("get new data");
});
this.t.onStart = function() {
console.info("starting timer");
};
this.t.onStop = function() {
console.info("timer stopped");
};
})
);
this.selectAutoRefresh.on("change", lang.hitch(this, function(value) {
if (value == "Automatic") {
this.t.start();
} else {
this.t.stop();
}
}));
},
When leaving the page the timer is still active so I want to stop it when I leave the page using DOJOs destroy() method.
destroy: function() {
this.t.stop();
},
This however throws a this.t.stop is not a function exception. It seems like this.t is not created in the context of the widget although I use lang.hitch(this...
What am I missing here?

I solved that by just renaming the variable t to refreshTimer. Maybe t is some kind of reserved variable in Dojo?

Multiple click handlers for a single element

I've written a few events to handle opening and closing of a snap js drawer. This code below works, but I feel it could be written more efficiently. Any suggestions?
function openMobileMenu() {
event.preventDefault();
snapper.open('left');
$('#btn-menu').off('click', openMobileMenu);
$('#btn-menu').on('click', closeMobileMenu);
}
function closeMobileMenu() {
event.preventDefault();
snapper.close('left');
$('#btn-menu').on('click', openMobileMenu);
$('#btn-menu').off('click', closeMobileMenu);
}
$('#btn-menu').on('click', openMobileMenu);

Make your code modular and your concepts explicit.
You can start by creating a MobileMenu object which encapsulates the logic.
Note: The following code was not tested.
var MobileMenu = {
_snapper: null,
_$button: null,
_direction: 'left',
init: function (button, snapper, direction) {
this._$button = $(button);
this._snapper = snapper;
if (direction) this._direction = direction;
this._toggleSnapperVisibilityWhenButtonClicked();
},
_toggleSnapperVisibilityWhenbuttonClicked: function () {
this._$button.click($.proxy(this.toggle, this));
},
toggle: function () {
var snapperClosed = this._snapper.state().state == 'closed',
operation = snapperClosed? 'open' : 'closed';
this._snapper[operation](this._direction);
}
};
Then in your page you can just do the following to initialize your feature:
var mobileMenu = Object.create(MobileMenu).init('#btn-menu', snapper);
Modularizing your code will make it more maintainable and understandable in the long run, but also allow you to unit test it. You also gain a lot more flexibily because of the exposed API of your component which allows other code to interact with it.
E.g. you can now toggle the menu visibility with mobileMenu.toggle().

Use a variable to keep track of the state:
var menu_open = false;
$("#btn-menu").on('click', function(event) {
event.preventDefault();
if (menu_open) {
snapper.close('left');
} else {
snapper.open('left');
}
menu_open = !menu_open; // toggle variable
});

snap has a .state() method, which returns an object stuffed with properties, one of which is .state.
I think you want :
$('#btn-menu').on('click', function() {
if(snapper.state().state == "closed") {
snapper.open('left');
} else {
snapper.close('left');
}
});
Or, in one line :
$('#btn-menu').on('click', function() {
snapper[['close','open'][+(snapper.state().state == 'closed')]]('left');
});
Also, check How do I make a toggle button? in the documentation.

Mootools event causes infinite loop in IE7/IE8

I have difficulties getting this to work in IE7 (and IE8).
Its a VERY reduced part of a much more complex script. So bear in mind that the methods and the structure cannot change too much.
In IE7 I get a infinite Loop when selecting one of the Types. In FF, Chrome and IE9 it works fine. It worked with mootools 1.1 Library in IE7/IE8 great too, but since I converted it to Mootools 1.4 i got that loop problem.
Maybe some kind of event delegation change in the framework. I really don't know.
Any help is greatly appreciated!
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>eventz</title>
<script src="https://ajax.googleapis.com/ajax/libs/mootools/1.4.5/mootools-yui-compressed.js" type="text/javascript"></script>
<script type="text/javascript">
var eventz = new Class({
options: {
},
initialize: function(options) {
this.setOptions(options);
this.setup();
this.jx = 0;
},
setup: function() {
this.makeEvents();
// ...
},
makeEvents : function() {
alert("init");
var finputs = $$('.trig');
finputs.removeEvents('change');
finputs.removeEvents('click');
finputs.each(function(r) {
$(r).addEvents({
'change': function(e) {
//e.preventDefault();
alert(r.name);
new Event(e).stop();
this.refresh(r); // this needs to stay as refresh calls some ajax stuff
}.bind(this)
});
}.bind(this));
// ...
},
// refresh is called from various methods
refresh : function(el) {
if(el) {
// count types checkboxes
var ob_checked = 0;
$$('.otypes').each(function(r) {
// uncheck all if clicked on "All"
if(el.id == 'typ-0') {
r.checked = false;
}
r.checked == true ? ob_checked++ : 0 ;
})
// check "All" if non selected
if(ob_checked == 0) {
$('typ-0').checked = true;
}
// uncheck "All" if some selected
if(el.id != 'typ-0' && ob_checked != 0) {
$('typ-0').checked = false;
}
// ajax call ...
}
}
});
eventz.implement(new Options);
window.addEvent('domready', function(){
c = new eventz();
});
</script>
</head>
<body>
<fieldset class="types">
<input type="checkbox" class="trig" name="otypes[]" value="0" id="typ-0" checked="checked">All
<input id="typ-14" value="14" name="otypes[]" type="checkbox" class="otypes trig">Type A
<input id="typ-17" value="17" name="otypes[]" type="checkbox" class="otypes trig">Type B
</fieldset>
</body>
</html>

Basically in MooTools 1.4.4+, change events have been 'normalized' in IE:
see this code: https://github.com/mootools/mootools-core/blob/master/Source/Element/Element.Event.js#L170-183
and this issue: https://github.com/mootools/mootools-core/issues/2170
which traces initial commits and the fixes.
With regards to your code, some changes need to take place:
new Event(e).stop(); must be rewritten to: e.stop();
implements method is now a mutator key: Implements
The whole thing can be simplified a lot. Here's a sample refactor, optimized for performance somewhat and with clearer logic.
http://jsfiddle.net/M2dFy/5/
something like:
var eventz = new Class({
options: {
},
Implements: [Options],
initialize: function(options) {
this.setOptions(options);
this.setup();
this.jx = 0;
},
setup: function() {
this.makeEvents();
// ...
},
makeEvents: function() {
var finputs = $$('.trig');
finputs.removeEvents('change');
finputs.removeEvents('click');
var self = this;
this.type0 = $('typ-0');
this.otypes = $$('.otypes');
this.pause = false; // stop flag because of IE
finputs.each(function(r) {
r.addEvents({
click: function(e) {
this.pause || self.refresh(r); // this needs to stay as refresh calls some ajax stuff
}
});
});
// ...
},
// refresh is called from various methods
refresh: function(el) {
this.pause = true;
if (el !== this.type0) {
// count types checkboxes
this.type0.set('checked', !this.otypes.some(function(other) {
return !!other.get("checked");
}));
// ajax call ...
}
else {
this.otypes.set('checked', false);
}
this.pause = false;
}
});
now, in view of the code you had, when you change .checked, it will trigger propertychange which will try to make the event bubble.
I would recommend changing all access to checked via the .set and .get methods, eg. el.set('checked', true); / el.get('checked') - similar use for id or any other property too.
Hopefully this is enough to set you on the right path, if you were to build an example of this in jsfiddle with a minimum DOM that works, I will be happy to look it over once more.
I have no IE here (mac) but I suspect it may break on clicking on a non-all checkbox as this will fire.
I would recommend moving to click events, though this will invalidate labels:
http://jsfiddle.net/M2dFy/4/