<!DOCTYPE qhelp PUBLIC

"-//Semmle//qhelp//EN"

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<qhelp>

<overview>

<p>

The <code>delete</code> operator should only be used to delete properties from objects. Using it

to delete variables makes code hard to maintain and will break in strict mode.

</p>

</overview>

<recommendation>

<p>

If the variable you are deleting is a global variable, this is a sign that your code relies too

much on global state. Try encapsulating this global state by means of one of the module patterns

introduced in <i>JavaScript: The Good Parts</i>.

</p>

</recommendation>

<example>

<p>

In the following code snippet, <code>delete</code> is used to clean up the global <code>cache</code>

variable used by function <code>get</code>.

</p>

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

<p>

It would be clearer to wrap the whole module into a closure like this (which also avoids exposing

function <code>compute</code> to the outside world):

</p>

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

</example>

</qhelp>