rot-js/manual/pages/util.html

A roguelike toolkit in JavaScript

<h2>Utilities</h2>

<p>Historically, <strong>rot.js</strong> was adding several new methods to JavaScript primordial objects: <code>Array</code>, <code>String</code>, <code>Number</code>, <code>Date</code>, <code>Object</code> and <code>Function</code>. This behavior is now frowned upon, so some of the provided functionality is now moved to the dedicated <code>ROT.Util</code> namespace.</p>


<h3>String</h3>

<p>A more verbose explanation about how <code>ROT.Util.format</code> works is available on a dedicated <a href="#format">string formatting page</a>.

<div class="example">
SHOW(
	ROT.Util.capitalize("hello world")
);</div>

<h3>Number</h3>

<p>The built-in modulus operator (%) yields negative results for negative arguments. <code>Number.prototype.mod</code> is guaranteed to return a positive value.</p>

<div class="example">
SHOW(
	( 15) % 7,
	(-15) % 7,
	ROT.Util.mod( 15, 7),
	ROT.Util.mod(-15, 7)
);</div>

<p>A numeric value often needs to be clamped into a useful range:</p>

<div class="example">
SHOW(
	ROT.Util.clamp( 15), // default range 0..1
	ROT.Util.clamp( 15, 0, 255), // custom range
	ROT.Util.clamp(-15, 0, 255)
);</div>