<!DOCTYPE qhelp PUBLIC

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

"qhelp.dtd">

<qhelp>

<overview>

<p>

Replacing a substring with itself has no effect and usually indicates a mistake, such as

misspelling a backslash escape.

</p>

</overview>

<recommendation>

<p>

Examine the string replacement to find and correct any typos.

</p>

</recommendation>

<example>

<p>

The following code snippet attempts to backslash-escape all double quotes in <code>raw</code>

by replacing all instances of <code>"</code> with <code>\"</code>:

</p>

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

<p>

However, the replacement string <code>'\"'</code> is actually the same as <code>'"'</code>,

with <code>\"</code> interpreted as an identity escape, so the replacement does nothing.

Instead, the replacement string should be <code>'\\"'</code>:

</p>

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

</example>

<references>

<li>Mozilla Developer Network: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String#Escape_notation">String escape notation</a>.</li>

</references>

</qhelp>