Object JavaScript – Code Walkthrough of a jQuery UI Widget

imageIn 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 – ECMAScript 6 Code Preview

imageECMAScript 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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Object JavaScript – ECMAScript 6 Futures Overview

imageECMAScript 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. ECMAScript is the foundation of JavaScript. ECMAScript has gone through several versions. The current browsers support ECMA Script 5. . The discussions today are revolving improvements beyond versions past 5, which are code-named, ECMAScript Harmony.

The ES6 compatibility table is very useful, as it tells us the ES6 features that are supported in the current browser. It also gives us a handy link to the specifications for each of the features listed.  You will find that the current versions of browsers are implementing these features as fast as they can. The table shows that some subset of the feature exists, so as we say,  “your mileage may vary”. That said, it is coming.

I don’t have any particular insider information, but wanted to share what I am learning as I explore ECMAScript 6 and what it means to the way that code is written today. In my search I found two great articles that I am pulling information from:

My value add is to provide context for the previous posts and show how your code in the future could look like to implement many of the same features. And this topic is fluid so again, “your mileage may vary”. My intent is to give you can idea of what is coming and how soon to help you decide how deeply you want to invest in the current technologies. That said, one of the goals in ECMAScript 6 is to not break anything you are doing now.

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Snippet – Checking Internet Connection, No More Hanging App

Messaging-Online-iconWhen 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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Snippets – Filtering JSON Using jQuery Grep, Filter, Map

6327_image_58FAEDFAWhen 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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