I'm using this page as a workspace. The talk page portion of it starts at #Discussions, below.

(Script under development - not yet functional)

When completed, this script will load the topics from holding bin into an array, then assists in placing each one.

This is the work area for developing the script and its documentation. The talk page portion of this page starts at #Discussions, below.

(Script under development - not yet functional)

TopicPlacerFromBin.js = Topic placer

When completed, this script will load the topics from holding bin into an array, then assists in placing each one.

This section explains the source code, in detail. It is for JavaScript programmers, and for those who want to learn how to program in JavaScript. Hopefully, this will enable you to adapt existing source code into new user scripts with greater ease, and perhaps even compose user scripts from scratch.

You can only use so many comments in the source code before you start to choke or bury the programming itself. So, I've put short summaries in the source code, and have provided in-depth explanations here.

My intention is Threefold:

1. to thoroughly document the script so that even relatively new JavaScript programmers can understand what it does and how it works, including the underlying programming conventions. This is so that the components and approaches can be modified, or used again and again elsewhere, with confidence. (I often build scripts by copying and pasting code that I don't fully understand, which often leads to getting stuck). To prevent getting stuck, the notes below include extensive interpretations, explanations, instructions, examples, and links to relevant documentation and tutorials, etc. Hopefully, this will help both you and I grok the source code and the language it is written in (JavaScript).
2. to refresh my memory of exactly how the script works, in case I don't look at the source code for weeks or months.
3. to document my understanding, so that it can be corrected. If you see that I have a misconception about something, please let me know!

In addition to plain vanilla JavaScript code, this script relies heavily on the jQuery library.

If you have any comments or questions, feel free to post them at the bottom of this page under Discussions. Be sure to {{ping}} me when you do.

An alias is one string defined to mean another. Another term for "alias" is "shortcut". In the script, the following aliases are used:

$ is the alias for jQuery (the jQuery library)

mw is the alias for mediawiki (the mediawiki library)

These two aliases are set up like this:

( function ( mw, $ ) {}( mediaWiki, jQuery ) );

That also happens to be a "bodyguard function", which is explained in the section below...

The bodyguard function assigns an alias for a name within the function, and reserves that alias for that purpose only. For example, if you want "t" to be interpreted only as "transhumanist".

Since the script uses jQuery, we want to defend jQuery's alias, the "$". The bodyguard function makes it so that "$" means only "jQuery" inside the function, even if it means something else outside the function. That is, it prevents other javascript libraries from overwriting the $() shortcut for jQuery within the function. It does this via scoping.

The bodyguard function is used like a wrapper, with the alias-containing source code inside it, typically, wrapping the whole rest of the script. Here's what a jQuery bodyguard function looks like:

1 ( function($) {
2     // you put the body of the script here
3 } ) ( jQuery );

See also: bodyguard function solution.

To extend that to lock in "mw" to mean "mediawiki", use the following (this is what the script uses):

1 ( function(mw, $) {
2     // you put the body of the script here
3 } ) (mediawiki, jQuery);

For the best explanation of the bodyguard function I've found so far, see: Solving "$(document).ready is not a function" and other problems   (Long live Spartacus!)

The ready() event listener/handler makes the rest of the script wait until the page (and its DOM) is loaded and ready to be worked on. If the script tries to do its thing before the page is loaded, there won't be anything there for the script to work on (such as with scripts that will have nowhere to place the menu item mw.util.addPortletLink), and the script will fail.

In jQuery, it looks like this: $( document ).ready(function() {});

You can do that in jQuery shorthand, like this:

$().ready( function() {} );

Or even like this:

$(function() {});

The part of the script that is being made to wait goes inside the curly brackets. But you would generally start that on the next line, and put the ending curly bracket, closing parenthesis, and semicolon following that on a line of their own), like this:

1 $(function() {
2     // Body of function (or even the rest of the script) goes here, such as a click handler.
3 });

This is all explained further at the jQuery page for .ready()

For the plain vanilla version see: http://docs.jquery.com/Tutorials:Introducing_$(document).ready()

Initially each script I write is made to work only on the vector skin, the skin under which I developed it, and by default the only skin for which it is initially tested with. To limit the script to working for vector only, I use the following if control structure:

if ( mw.config.get( 'skin' ) === 'vector' ) {
}

To test it with another skin, remove or comment out the above code from the script.

Completed features are marked with  Done