=proto
int duk_has_var(duk_context *ctx);

=stack
[ ... varname! ] -> [ ... ]

=summary
FIXME

<p>The identifier existence check does not have a direct Ecmascript equivalent.
The closest equivalent is:</p>
<pre class="ecmascript-code">
typeof varname !== 'undefined'
</pre>

<p>However, if the identifier is defined but has the value <code>undefined</code>,
the above check gives a different result than this API call.  Note that the
value of the identifier is not looked up and there can thus be no side effects
from e.g. getter calls.</p>

=tags
variable
omit

=example
FIXME

=fixme
Incomplete.