UniqueParameterNames.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
  "qhelp.dtd">
<qhelp>
<overview>
<p>
In non-strict mode, JavaScript allows a function to have several parameters with the same name, where
later parameters shadow earlier parameters. This is an error-prone feature which makes code hard to
understand and should be avoided.
</p>

</overview>
<recommendation>

<p>
Rename the parameters to have different names.
</p>

</recommendation>
<example>

<p>
In the following example, function <code>f</code> has two parameters named <code>x</code>, the
second one presumably being a typo for <code>y</code>. Since no parameter <code>y</code> is declared,
the use of <code>y</code> in the body of <code>f</code> refers to a global variable of that name, if
it exists.
</p>

<sample src="examples/UniqueParameterNames.js" />

<p>
Duplicate parameter names are illegal in strict mode.
</p>

</example>
<references>


<li>Ecma International, <i>ECMAScript Language Definition</i>, 5.1 Edition, Annex C. ECMA, 2011.</li>


</references>
</qhelp>