Develop Reference

Use Javascript Object to Angular Service

I am trying to add functions to a JS Object which will be used as a singleton service.
angular
.module('app.steps')
.factory('createStepsService', createStepsService);
createStepsService.$inject = [];
/* #ngInject */
function createStepsService() {
var steps;
var service = {
newSteps: function (current_step, total_steps) {
if (!steps) {
return new Steps(current_step, total_steps);
}
}
};
return service;
function Steps(current_step, total_steps) {
this.c_step = current_step;
this.t_step = total_steps;
}
Steps.prototype = {
addSteps: function (num) {
this.c_step += num;
},
setLastStep: function () {
this.lastStep = this.c_step = this.t_step;
}
};
}
When I run this line from the controller, I am not able to access
addSteps / setLastStep methods.
vm.createStepsService = createStepsService.newSteps(1, 3);
Why I don't see these methods? Were they created?
Thanks.

Your steps.prototype code is never ran.
This is because it appears after the return.
Change the order of your code to this:
/* #ngInject */
function createStepsService() {
var steps;
function Steps(current_step, total_steps) {
this.c_step = current_step;
this.t_step = total_steps;
}
Steps.prototype = {
addSteps: function (num) {
this.c_step += num;
},
setLastStep: function () {
this.lastStep = this.c_step = this.t_step;
}
};
var service = {
newSteps: function (current_step, total_steps) {
if (!steps) {
return new Steps(current_step, total_steps);
}
}
};
return service;
}
The reason that you can have a function declared before a return is because of JavaScript variable and function hoisting.

Your problem is that you are creating Steps.prototype after a return statement, so it will never be read.

In AngularJS, services are singletons objects that are instantiated only once per app.
And the factory() method is a quick way to create and configure a service.
It provides the function's return value i.e. Need to create an object, add properties to it, then it will return that same object.
For ex:
angular
.module('myApp',[])
.factory("createStepService", function(){
var stepServiceObj = {};
var c_step = 0;
var t_steps = 0;
var last_step = 0;
stepServiceObj.setCurrentStep = function(current_step){
c_step = current_step;
console.log('c_step1: ',c_step);
};
stepServiceObj.getCurrentStep = function(){
return c_step;
};
stepServiceObj.setTotalStep = function(total_steps){
t_steps = total_steps;
};
stepServiceObj.getTotalStep = function(){
return t_steps;
};
stepServiceObj.setLastStep = function(){
last_step = c_step = t_step;
};
stepServiceObj.getLastStep = function(){
return last_step;
};
stepServiceObj.addSteps = function(num){
return c_step += num;
};
return stepServiceObj;
});

A Javascript function which creates an object which calls the function itself

I am trying to make an angular service that returns a new object.
That's fine and good and works. new MakeRoll() creates an instance. But self.add, near the end also calls new MakeRoll() and that doesn't create an instance when I call add like I think it should.
I'm probably doing this all wrong but I haven't been able to figure it out.
var services = angular.module('services', []);
services.factory('Roll', [function() {
var MakeRoll = function () {
var self = {};
self.rolls = [];
self.add = function(number, sizeOfDice, add) {
var newRoll = {};
newRoll.number = number || 1;
newRoll.sizeOfDice = sizeOfDice || 6;
newRoll.add = add || 0;
newRoll.rollDice = function() {
var result = 0;
var results=[];
for (var i = 0; i < newRoll.number; i++) {
var roll = Math.floor(Math.random() * newRoll.sizeOfDice) + 1;
result += roll;
results.push(roll);
}
newRoll.results = results;
newRoll.result = result;
newRoll.Roll = new MakeRoll();
};
self.rolls.push(newRoll);
return self;
};
self.remove = function(index) {
self.rolls.splice(index, 1);
};
self.get = function(index) {
return self.rolls[index];
};
return self;
};
return new MakeRoll();
}
]);

angular service is designed to be singleton to accomplish some business logic, so don't mix up plain model with angular service. if you want to have more objects, just create a constructor and link it in service to be operated on.
function MakeRoll() {
...
}
angular.module('service', []).factory('Roll', function () {
var rolls = [];
return {
add: add,
remove: remove,
get: get
}
function add() {
// var o = new MakrRoll();
// rolls.push(o);
}
function remove(o) {
// remove o from rolls
}
function get(o) {
// get o from rolls
}
});

Javascript Composite pattern, can not use overwritten methods correctly

I have a javascript compositer pattern which i implemented (see code below).
In my main class i instantiate either the MenuItem or the Menu. I have to call the method update() on the component and they should return the corresponding code.
However it doesnt return the correct amount of totalitems. it alwasy returns the default value 0 which is defined in MenuComponent.
I think it has something to do with the this keyword but i can not find the exact solution.
MenuItem:
//MENU ITEM
//----------
var MenuItem = function(id) {
MenuComponent.apply(this, [id, name]);
};
MenuItem.prototype = Object.create(MenuComponent.prototype);
MenuItem.prototype.constructor = MenuItem;
MenuItem.prototype.update = function() {
//works
console.log(this.ingredients)
//Doesnt work, this should display same as this.ingredients
console.log(this.calculateIngredients())
console.log("--------------")
};
Menu:
//MENU
//--------
var Menu = function(id, name) {
MenuComponent.apply(this, [id, name]);
this.menuitems = [];
};
Menu.prototype = Object.create(MenuComponent.prototype);
Menu.prototype.constructor = Menu;
Menu.prototype.add = function(menuitem) {
this.menuitems.push(menuitem);
};
Menu.prototype.remove = function(menuitem) {
for(var s, i = 0; s = this.getMenuItem(i); i++) {
if(s == menuitem) {
this.menuitems.splice(i, 1);
return true;
}
if(s.remove(menuitem)) {
return true;
}
}
return false;
};
Menu.prototype.getMenuItem = function(i) {
return this.menuitems[i];
};
Menu.prototype.calculateIngredients = function() {
this.ingredients = 0;
for(var key in this.menuitems) {
this.ingredients += this.menuitems[key].calculateIngredients();
}
return this.ingredients;
};
MenuComponent
//MenuComponent
//-------------
var MenuComponent = function(id, name) {
if(this.constructor === MenuComponent) {
throw new Error("Can't instantiate abstract class");
}
this.id = id;
this.name = name;
this.ingredients = 0;
};
MenuComponent.prototype.calculateIngredients = function() {
return this.ingredients;
};
MenuComponent.prototype.update = function() {
console.log(this.ingredients)
console.log("-----------------")
};
example
// HANDLER
var menuitem1 = new MenuItem(1)
, menuitem2 = new MenuItem(2)
, menuitem3 = new MenuItem(3)
, menuitem4 = new MenuItem(4)
, menuitem5 = new MenuItem(5)
, menuitem6 = new MenuItem(6)
, menuitem7 = new MenuItem(7)
, menu = new Menu(1);
menu.add(menuitem1);
menu.add(menuitem2);
menu.add(menuitem3);
menu.add(menuitem4);
menuitem1.ingredients = 1
menuitem2.ingredients = 5
menuitem3.ingredients = 7;
menuitem4.ingredients = 2
// lets say i want to update the ingredient count of the following
menuitem1.update();
menuitem2.update();
menu.update();
//the update goes wrong, it doesnt display the correct amount, it alwasy displays 0 on the amounts where i commented
JSFiddle

Instead of
MenuComponent.prototype.update = function() {
console.log(this.ingredients) // 0
};
You want to call
MenuComponent.prototype.update = function() {
console.log(this.calculateIngredients()) // 15
};
whole code on jsfiddle: http://jsfiddle.net/krzysztof_safjanowski/gjTb4/

Best practice to 'combine' jQuery methods

I'm in the process of creating a customized filter plugin for jQuery.
So far' I've managed to implement the following code:
(function ($) {
$.fn.filterbyDate = function (filterValue) {
var tableDate = new Date($(':eq(3)', $(val)).text());
var days = numDaysBetween(tableDate, new Date());
if (filterValue === "-1") {
$(val).show();
} else {
switch (filterValue) {
case "This Week":
if (days > 7) {
$(val).hide();
} else {
$(val).show();
}
break;
case "This Month":
if (days > 30) {
$(val).hide();
} else {
$(val).show();
}
break;
case "This Year":
if (days > 365) {
$(val).hide();
} else {
$(val).show();
}
break;
default:
}
}
};
$.fn.filterbyClient = function (filterValue) {
var $table = $(".tablefilter");
$.each($table.find("tbody>tr"), function (ind, val) {
var name = $(':eq(2)', $(val)).text();
if (filterValue === "-1") {
$(val).show();
} else {
if (name.trim() !== filterValue) {
$(val).hide();
} else {
$(val).show();
}
}
});
};
}(jQuery));
It's implemented by:
controller1.filterByDate(date);
controller2.filterByClient(client);
This works exactly as it should separately, but when I try 'filterByClient' after 'filterByDate', it naturally overwrites the former for the latter.
So essentially I would like to filterByClient based on the results on filterByDate
Is there any best practice for somehow 'combining' methods where need be, to filter only on the latest results?
Note: The methods are called by two different controllers (select lists)
Eg:
$("#dateFilter").change(function () {
$(this).filterbyDate($(this).val());
});
$("#clientFilter").change(function() {
$(this).filterbyClient($(this).val());
});

You can use method chaining. Just return this; at the end of your functions and use them like controller.filterByDate(date).filterByClient(client);
So your methods would look like
$.fn.filterbyDate = function (filterValue) {
//Do Stuff
return this;
};
$.fn.filterbyClient = function (filterValue) {
// Do Stuff
return this;
};
EDIT:
If its used by different controllers, you have to abstract your controllers, so that the methods don't have to filter the controllers itself, but a list which they use.
So you can do something like:
var list = controller1.list.filterByDate(date);
controller2.list = list.filterByClient(client);

You could pass the list to be filtered as an argument to your function:
(function ($) {
$.fn.filterbyDate = function (list, filterValue) {
var filteredList = [];
//apply filter on list and put result into filteredList...
return filteredList;
};
$.fn.filterbyClient = function (list, filterValue) {
var filteredList = [];
//apply filter on list and put result into filteredList...
return filteredList;
};
}(jQuery));
var entireList = [...];
var filterdList = controller1.filterByDate(entireList, date);
var doubleFilteredList = controller2.filterByClient(filterdList , client);
Update:
Or merge your filter functions into 1 and allow multiple fields to be filtered at once:
$.fn.filterby = function (options) {
//apply filters
if (options.date !== undefined) {
// apply date filter based on value of options.date
}
if (options.client !== undefined) {
// apply client filter on value of options.client
}
};

How to iterate anonymous function inside each function in Knockout viewmodel

I am building a Knockout viewmodel. The model has some fields like dateFrom, DateTo, Status and so forth. In addition, there is a list of invoices.
The invoices have some pricing information, which is a price object. My main object also have a price object, which should iterate all the invoice objects and find the total price.
My problem is the following:
The code runs smooth, until I add the following in my view:
<label data-bind="text:totalPrice().price().priceExVat"></label>
Here I get an:
TypeError: $(...).price is not a function
Which refers to my:
exVat += $(ele).price().priceExVat;
I don't understand it, because in my each function, I should have the element. The element have a price() function, so why would it not work? Is it some scope issue?
My viewmodel:
function invoice(invoiceDate, customerName, pdfLink, status) {
var self = this;
self.pdfLink = pdfLink;
self.print = ko.observable(0);
self.customerName = customerName;
self.status = status;
self.pdfPagesCount = function () {
return 1;
};
self.invoiceDate = invoiceDate;
self.price = function () {
return new price(1.8, 2.1);
};
}
function price(exVat, total) {
var self = this;
self.currency = '€';
self.total = total;
self.priceExVat = exVat;
self.vatPercentage = 0.25;
self.vatAmount = self.exVat - self.total;
self.priceExVatText = function() {
return self.priceExVat + ' ' + self.currency;
};
}
var EconomicsViewModel = function (formSelector, data) {
var self = this;
self.dateFrom = data.dateFrom;
self.dateTo = data.dateTo;
self.invoices = ko.observableArray([
new invoice('05-05-2014', 'LetterAmazer IvS', "http://www.google.com","not printed"),
new invoice('05-05-2014', 'LetterAmazer IvS', "http://www.google.com", "not printed")
]);
self.totalPrice = function () {
var exVat = 0.0;
$(self.invoices).each(function (index, ele) {
console.log(ele);
exVat += $(ele).price().priceExVat;
});
return price(exVat, 0);
};
};

From what I read, totalPrice is actually a price object, you don't need to put a .price():
<label data-bind="text:totalPrice().priceExVat"></label>
EDIT:
Sorry, there were also problems on your javascript:
self.totalPrice = function () {
var exVat = 0.0;
$(self.invoices()).each(function (index, ele) { //<-- add () to self.invoices to get the array
console.log(ele);
exVat += ele.price().priceExVat; //<-- remove useless jQuery
});
return new price(exVat, 0); //<-- add 'new'
};
Check this fiddle
EDIT2:
To answer robert.westerlund's comment, you could remove $().each and replace with ko.utils.arrayForEach or even simpler use a for loop:
var arr = self.invoices();
for (var i = 0; i < arr.length; i++) {
console.log(arr[i]);
exVat += arr[i].price().priceExVat;
}
Updated fiddle