JavaScript supports four types of basic data structures

Submitted by gwagner on Wed, 03/04/2015 - 16:11

The four types of basic data structures supported by JavaScript are: array lists, maps, records and JSON tables. The following list provides a summary:

Array lists, such as ["one","two","three"], are special JS objects called 'arrays', but since they are dynamic, they are rather array lists as defined in the Java programming language.
Maps are also special JS objects, such as {"one":1,"two":2,"three":3}, as discussed below.

Enumerations and Enumeration Attributes in JavaScript

Submitted by gwagner on Wed, 02/18/2015 - 01:50

In all application domains, there are enumeration datatypes that define the possible values of enumeration attributes. We show how to implement an enumeration in the form of a special JavaScript object definition using the Object.defineProperties method.

AngularJS does not have a model: it's not MV, but rather VM

Submitted by gwagner on Wed, 02/11/2015 - 14:54

Where is the "model" in AngularJS? The answer to this question is:

AngularJS does not work with a real model but just with a view model. Therefore, it shouldn't be called an MVC framework, and neither an MVW nor an MV* framework, but rather a View-Model-Whatever (or VM*) framework.

Expressing Date/Time Information with the <time> Element

Submitted by gwagner on Thu, 01/29/2015 - 12:41

While date/time information items have to be formated as strings in a human-readable form on web pages, preferably in localized form based on the settings of the user's browser, it's not a good idea to store date/time values in this form. Rather we use instances of the pre-defined JavaScript class Date for representing and storing date/time values.

Storing database tables in JavaScript's Local Storage

Submitted by gwagner on Tue, 01/20/2015 - 16:44

In most apps we have some form of data management where data is represented in tables such that table rows correspond to objects, anf the table schema corresponds to the objects' type. When building a front-end web app with JavaScript, the simplest approach for persistent data storage is using JavaScript's localStorage API, which provides a simple key-value database, but does not support database tables. So, the question is: how can we store and retrieve tables with Local Storage?

Why are associations so difficult to understand, not just for developers?

Submitted by gwagner on Fri, 11/21/2014 - 15:30

Class diagram with a chair association between classes Committee and ClubMember In summary, the answer to this question is: because unlike the general concept of an object type or class, the general concept of an association, as defined by UML, does not have a direct computational counterpart, neither in common object-oriented (OO) programming languages, nor in SQL.

What's the difference between a JavaScript object and a UML/Java object?

Submitted by gwagner on Mon, 11/17/2014 - 17:44

In standard OO, as defined by UML, and instantiated by Java, there is a certain concept of object. What's the difference between this classical concept of objects and a JavaScript object?

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