MissingExports.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
  "qhelp.dtd">
<qhelp>

<overview>
<p>
Referencing an otherwise undeclared global variable in a module that exports
a definition of the same name is confusing and may indicate a bug.
</p>
</overview>

<recommendation>
<p>
If the global variable reference is intentional, consider adding a JSLint
<code>/*global ...*/</code> directive or an externs declaration to declare the variable.
</p>
<p>
If the global variable reference is unintentional, qualifying the reference
with <code>exports</code> will make it refer to the exported definition instead.
</p>
</recommendation>

<example>
<p>
In the following example, the module exports two functions <code>checkOne</code>
and <code>checkList</code>. The latter is also stored in a variable of the same name
that is local to the module, but the former is not. Hence the call <code>checkOne(xs[i])</code>
on line 7 does not refer to the function defined on line 1, but to an otherwise undeclared
global variable also called <code>checkOne</code>.
</p>

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

<p>
Assuming that the intention is to call the <code>checkOne</code> function defined on line 1,
the call should be qualified with <code>exports</code> like this:
</p>

<sample src="examples/MissingExportsGood.js" />
</example>

<references>
<li>Node.js: <a href="https://nodejs.org/api/modules.html">Modules</a>.</li>
<li>JSLint Help: <a href="http://www.jslint.com/help.html">JSLint Directives</a>.</li>
<li>Closure Compiler: <a href="https://developers.google.com/closure/compiler/docs/api-tutorial3">Advanced Compilation and Externs</a>.</li>
</references>
</qhelp>