jQuery – AzureDays

Object JavaScript – Code Walkthrough of a jQuery UI Widget

February 26, 2015

In the last post, Building Stateful jQuery UI Plugin Using Widget Factory, you were introduced to the working structure of jQuery UI Widgets. You learned that it uses the factory pattern is a way to generate different objects with a common interface. And that it Widget Factory adds features to jQuery plug-in.

jQuery UI Widget Factory is under jQuery UI, but you can use it separately for your own widgets. In this post, you will learn the steps you can take to build your own widget. This posts walks through an implementation of the filterable dropdown from Adam J. Sontag’s and Corey Frang’s post: The jQuery UI Widget Factory WAT?

My motivation in this post is to show what goes where when you are designing your widgets. And provide some direction in the steps you can take when building a widget from scratch.

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Object JavaScript – Building Stateful jQuery UI Plugin Using Widget Factory

February 25, 2015

In this post, you will learn step-by-step to build your own custom, reusable, testable jQuery UI widget.

You will extend the jQuery library with custom UI code and then use it on a page. The initial plug-in will be trivial to demonstrate the jQuery Widget Factory pattern. You will provide properties that you can change to change the look of your widget and you will provide some methods that will respond to user input.

In this post example, you will learn how to create a simple click counter. Click a button, increase the count. The idea is to show you the steps to create a jQuery UI Widget.

The Widget Factory system manages state, allows multiple functions to be exposed via a single plugin, and provides various extension points.

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Object JavaScript – Building a Reusable Stateless jQuery Plugin

February 23, 2015

In this post, you will learn step-by-step to build your own custom, reusable, testable jQuery Plugin.

There are times where you will want to reuse code that performs a series of operations on a selection.

For example, you may want to embed information a span element and then have that information displayed in a references section near the end of the document. In this case, the jQuery plugin is stateless.

In the next post, Building Stateful jQuery UI Plugin Using Widget Factory, you will see how to create a stateful jQuery plugin using jQuery Widget. And you will see how the widget is a better solution for plugins that require user interaction, because the Widget factory helps you maintain state.

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Object JavaScript – ECMAScript 6 Code Preview

December 17, 2014

ECMAScript 6 specification and implementation is underway and promises to bring many of the features that you’ve learned about in the posts on Object JavaScript.

This post gives you an idea of what the code looks like in ECMAScript 6. This post doesn’t cover ever feature. But you will learn about how ECMAScript 6 relates to:

Scope
Arrow Functions and Lexical this
Default Function Parameters
Classes
Inheritance
Modules
for-of
Arrow functions
Promises

I won’t come close to covering all the features. But you can get an idea of how ECMAScript 6 works to support the idea of Object JavaScript. Look to the references and to the specification for information about: Parameter handling, multiple return values, collections, destructuring, rest parameters & spread operator, iterators, array comprehension, and more.

Special thanks to Axel Rauschmayer for many of the snippets.

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Snippet – Checking Internet Connection, No More Hanging App

July 22, 2014

When you are writing your single page application (SPA) may find that you need to check your connection. The idea is that you might have one set of logic for your connected app and another for when you are disconnected.

In previous posts, AppCache for Offline Apps and Loading, Caching LoDash or Underscore Templates Using RequireJS, AppCache, you learned that your Web app did not have to be online to be run. In fact, when building HTML apps for mobile devices, you are running without a connection.

So how do you check? How do you know when you can upload and download new information from the Web?

Many of the comments on StackOverflow have to do with the connection hanging. The following snippets help you work around the issue.

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Object JavaScript – Code Walkthrough Initializing a Module That Needs RequireJS, jQuery, LoDash

July 19, 2014

RequireJS is a JavaScript file and module loader. In Getting Started with Modules Using RequireJS, you have learned a lot about how you can use it to load your dependencies using define() and require().

In this code snippet, you will learn how you can load the dependencies, initialize a module with values that you pass in, and then make public some of the methods.

And you will see how to put files in folders to help keep identify which modules you write in your app and which modules are from third parties.

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Snippets – Filtering JSON Using jQuery Grep, Filter, Map

July 13, 2014

When you have a JSON array, you may want to get one or more items from the array and display. jQuery offers two functions that can help: grep and filter.

$.grep(). Finds the elements of an array which satisfy a filter function. The original array is not affected.
$filter(). Reduce the set of matched elements to those that match the selector or pass the function’s test.
$.map(). applies a function to each item in the array, thus returning a modified array

In other words, $.grep() removes items from an array as necessary so that all remaining items pass a provided test; .filter() constructs a new jQuery object from a subset of the matching elements.

Also, filter is intended to be used with html elements, and that is why it is a chainable function that returns a jQuery object and it accepts filters like “:even”, “:odd” or “:visible” etc. You can’t do that with the grep function, which is intended to be a utility function for arrays.

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Single Page App – isLoading jQuery Plugin to Indicate Content Loads

July 12, 2014

When you’re loading information using jQuery AJAX, you may want to provide visual feedback when loading data or for any action that would take time.

In this Snippet, you will learn how to:

Load JSON data from a getJSON call to our server.
Show and hide a spinning indicator inside a div.
Bind the incoming data to a view model object.
Use the view model to populate an external template.

Then once the page is loaded, it will display the data based on an external template.

And we’ll provide some tips on how you you can use the IsLoading library to display the loading indicator on top of the page while loading and on top of the div itself.

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Snippet – C#, JavaScript, jQuery, Underscore ForEach Loops

July 11, 2014

The foreach statement repeats a group of embedded statements for each element in an array or an object collection. The foreach statement is used to iterate through the collection to get the information that you want.

It is not be used to add or remove items from the source collection to avoid unpredictable side effects. (If you need to add or remove items from the source collection, use a for loop.)

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