function expression with namespace - javascript

Actually I am trying to have a namspace [to avoid global variables] without object creation and trying to do the below. But, the execution of the methods data.sum and data.calc.mult with alerts is not getting called. Instead the empty declarations inside data are called. Can I anyone help me know why this is happening?
var data = {
name: "",
sum: function() {},
calc : {
mult: function() {}
}
};
data.sum();
data.calc.mult();
data.sum = function () {
alert('sum');
};
data.calc.mult = function () {
alert('mult');
};

If you put your data.sum() after data.sum function redefinition, you will get the alert box.

Define it like this (function definition within object definition):
var data = {
sum: function () {
alert('sum');
},
mult: function () {
alert('mult');
}
};
data.sum();
data.mult();

Related

How to use a variable inside itself

I want to use the variable inside itself and I see other people do it but why does it not work for me?
This is my ES6 file
// Setup module
// ------------------------------
var FullCalendarAdmin = function () {
//
// Setup module components
//
var _componentRender = function () {
// Basic calendar
var _componentFullCalendarAdmin = function (events) {
// Define element
var calendarAgendaViewElement = document.querySelector('.fullcalendar-agenda-admin');
// Initialize
if (calendarAgendaViewElement) {
var calendarAgendaViewInit = new FullCalendar.Calendar(calendarAgendaViewElement, {
plugins: ['dayGrid', 'timeGrid', 'interaction'],
select: function (start, end) {
var title = prompt("Add event:");
var data;
if (title != '') {
data = {
title: title,
start: start,
end: end
};
calendarAgendaViewInit.addEvent(data);
}
}).render();
}
};
//
// Return objects assigned to module
//
return {
init: function () {
_componentRender();
}
}
}();
// Initialize module
// ------------------------------
document.addEventListener('DOMContentLoaded', function () {
FullCalendarAdmin.init();
});
How can I use the calendarAgendaViewInit to call the addEvent function without getting function as an undefined error?
Thanks in advance!
The problem is that you invoke .render immediately.
So your calendarAgendaViewInit is not an instance of FullCalendar.Calendar but the result of the render method.
What you can do is first define the calendarAgendaViewInit variable
var calendarAgendaViewInit = new FullCalendar.Calendar(calendarAgendaViewElement, {
plugins: ['dayGrid', 'timeGrid', 'interaction'],
select: function (start, end) {
var title = prompt("Add event:");
var data;
if (title != '') {
data = {
title: title,
start: start,
end: end
};
calendarAgendaViewInit.addEvent(data);
}
});
and then call calendarAgendaViewInit.render().
This is sort of an expanded explanation to the comment above. It looks like calendarAgendaViewElement is simply a DOM element that you've found and assigned to a variable. The problem here is that you can only call methods on class instantiations that are now objects with methods inside. If you had seen others call addEvent like that, then they were likely calling it on an instantiation of a class meaning that addEvent had been previously declared as part of that class and they are simply calling that method.
See the example below,
If I declare a class as follows:
class Sample {
sayHello(){
console.log('hello')
}
}
Then instantiate a new object of the 'Sample' class:
var sampleClass = new Sample()
Then I can call 'sayHello' by referring to the method inside the object
sampleClass.sayHello() // hello
Hope that helps

combine multiple functions with same code in jquery

Yes, I have thoroughly searched google and did not find anything that suits my requirement.
The code i have so far is at the link below:
http://jsfiddle.net/ZKwTY/4/
There are multiple onchange events which call almost the same code, i would like to combine them maybe in a comma separated fashion to call it only once.
something like this
(on1Change, on2Change, on3Change): function () {
this.loadData();
}
is this possible??
Note: these functions are bound to the controls via a framework over which i do not have control, i need to create these functions and the framework would bind these to the respective controls
or you can create your object like this
var ol = {
on1Change: this.loadData,
on2Change: this.loadData,
on3Change: this.loadData,
on4Change: this.loadData,
loadData: function () {
this.loadData1();
this.loadData2();
},
loadData1: function () {
alert('hi from loadData1');
},
loadData2: function () {
alert('hi from loadData2');
}
};
Then if you want to do it once, then declare a object
var ol = {
loadData: function () {
this.loadData1();
this.loadData2();
},
loadData1: function () {
alert('hi from loadData1');
},
loadData2: function () {
alert('hi from loadData2');
}
};// end of object
ol.on1Change = ol.on2Change = ol.on3Change = ol.on4Change = ol.loadData;
add all propteries dynamically after object declaration
use bind()
$("selector").bind(on1Change, on2Change, on3Change): function () {
this.loadData();
}.....
you can try somethig like this http://jsfiddle.net/s4VVY/
i.e. add methods after object create
[1,2,3,4,5].forEach(function(it){ol["on"+it+"Change"] = function(){this.loadData()}})
UPDATE
may be this help
var ol = (function(){
var o = {
loadData: function () {
this.loadData1();
this.loadData2();
},
loadData1: function () {
alert('hi from loadData1');
},
loadData2: function () {
alert('hi from loadData2');
}
}
o.on1Change=o.on2Change=o.on3Change=o.on4Change=function(){ this.loadData();};
return o;
})()
also you can make function bindFunc
function bindFunc(){
var obj = arguments[0],
handler = arguments[1],
properties = Array.prototype.slice.call(arguments,2);
for(var i in properties){
obj[properties[i]] = handler;
}
}
and call as
bindFunc(o,function(){this.loadData();},"on1Change","on2Change","on3Change","on4Change")

Better way of making javascript function a property

I was wondering if there was a way to use the get function in the url object below to generate property without wrapping it in an anonymous function.
It may be because I am just starting to dig into JavaScript after starting with jQuery, but something seems weird about wrapping a property in a anonymous function just to concatenate a string.
Current Object
var app = {
settings: {
webservice: 'http://abc.com/webservice/',
url: {
get: function (method) {
return app.settings.webservice + method;
},
caseSearch: function () {
return this.get('GetCases');
},
tipSearch: function () {
return this.get('GetTips');
},
propertySearch: function () {
return this.get('GetProperty');
}
}
}
};
Current
var url = app.settings.url.caseSearch();
Proposed
var url = app.settings.url.caseSearch;

Expose knockout ViewMode from function to another function

I have next situation...
For some reasons I need to bind knockout ViewModel inside function and call it on specific terms.
this is my code:
if (... some conditions ...) {
var polugodiste = $("#polugodiste").val();
ApplyBindingsIzostanak(polugodiste);
$('#flip-min').change(function () {
IzostanakViewModel.selectedPolugodiste(parseInt($(this).val()));
IzostanakViewModel.GetIzostanci();
});
}
and function:
function ApplyBindingsIzostanak(polugodiste)
{
var Izostanak = function (cas, tekst) {
this.Cas = cas;
this.Tekst = tekst;
};
var IzostanakViewModel = {
selectedStatus: ko.observable(),
selectedPolugodiste: ko.observable(polugodiste),
ucenikIzostanakList: ko.observableArray([]),
GetIzostanci: function () {
.. do some code ...
}
};
ko.applyBindings(IzostanakViewModel);
}
Binding is working, but I get error when I try calling IzostanakViewModel inside my if, it says IzostanakViewModel is not defined.
Can I and how expose IzostanakViewModel from function and use it inside if statement?
NOTE*
I could try something like this:
add this code to ApplyBindingsIzostanak():
window.foo = function() {
IzostanakViewMode.GetIzostanci();
}
and then call it from if statement, but maybe there is better solution...
IzostanakViewModel is a variable within the ApplyBindingsIzostanak() function. Why don't you just return it so you have a reference to it?
function ApplyBindingsIzostanak(polugodiste)
// ...
return IzostanakViewModel;
}
var IzostanakViewModel = ApplyBindingsIzostanak(polugodiste);
$('#flip-min').change(function () {
IzostanakViewModel.selectedPolugodiste(parseInt($(this).val()));
IzostanakViewModel.GetIzostanci();
});

Invoke public function from internal/private function?

Just wondering if I'm missing something or not but I attempted to do the following:
(function() {
var thing = function() {
var doIt = function() {
console.log("just do it");
this.updateValue(5);
};
return {
updateValue: function(val) {
console.log('updating value: ' + val);
},
go: function() {
doIt();
}
}
};
var t = thing();
t.go();
}())
This results in "just do it" showing up in the console followed by an error b/c it says "updateValue" is not a function.
I was wondering, can an internal/private function (e.g. "doIt") invoke a public function (e.g. "updateValue")? Perhaps this is just bad design and you should never really want to do this and I've actually refactored my code to avoid/not do this but I was curious if it was possible.
Thanks in advance.
Either use call/apply to explicitly specify the context for this (like #SLaks and #Alnitak) mentioned or else define the function at the beginning and then add it as a property to the returned object:
var thing = function() {
var updateValue = function () { /* */ },
doIt = function() {
console.log("just do it");
updateValue(5);
};
return {
updateValue: updateValue, // minor duplication here
go: function() {
doIt();
}
};
};
If the minor duplication annoys you, you can also do this:
var thing = function() {
var exposed = {
updateValue: function(val) {
console.log('updating value: ' + val);
},
go: function() {
doIt();
}
}, doIt = function() {
console.log("just do it");
exposed.updateValue(5);
};
return exposed;
};
Writing doIt(), calls the function in the global context, so this is the window object.
You need to write doIt.call(this) to pass your this as the context for doIt.
Per #SLaks answer, this is incorrect when invoked by doIt().
Instead, try:
doIt.call(this);

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