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2020-07-25T15:52:24Z

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{{Coding Standards Index}}

BOARD18 uses '''var''' to define all JavaScript variables.
This practice should be continued if only for consistancy.

There are a lot of "best practices" documents on the web
that warn coders to avoid variables that are scoped outside
of any function. OOP is all about "locality of reference".
This makes sense if you are including libraries which may,
by chance, use the same variable names. That can cause chaos.

But BOARD18 is a maverick in this respect. JavaScript functions
in BOARD18 often access "global" variables. Information is passed
in massive structures that are updated in various places.

BOARD18 uses the following trick to partially mitigate this
potential problem.

All board18 'global' variables are contained
in one 'master variable' called '''BD18'''. This isolates
them from global variables in other packages.

At the front of the board18com.js file, which is included in
every BOARD18 page, is the following 5 lines of code:
<pre>
var BD18 = {};
BD18.noteTimeout = null; // Used by doLogNote().
BD18.welcomename = null; // Used by doLogNote().
BD18.help = "https://wiki.board18.org/w/Player%27s_Guide_V2.5";
BD18.version = "2.5.11";
</pre>
Thus the '''BD18''' object becomes the only global
variable in BOARD18. Many objects and arrays will be
added to this object. But it still remains only one variable.

[[Category:Standards]]

Coding Standards Variables - Revision history

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