=proto
void duk_enum(duk_context *ctx, int obj_index, int enum_flags);

=stack
[ ... obj! ... ] -> [ ... obj! ... enum! ]

=summary
<p>Create an enumerator for object at <code>obj_index</code>.  Enumeration
details can be controlled with <code>enum_flags</code>.  If the target value
is not an object, throws an error.</p>

<p>Enumeration flags:</p>
<ul>
<li><code>DUK_ENUM_INCLUDE_NONENUMERABLE</code>: enumerate also non-enumerable
    properties (by default only enumerable properties are enumerated)</li>
<li><code>DUK_ENUM_INCLUDE_INTERNAL</code>: enumerate also internal properties
    (by default internal properties are not enumerated)</li>
<li><code>DUK_ENUM_OWN_PROPERTIES_ONLY</code>: enumerate only an object's "own"
    properties (by default also inherited properties are enumerated) </li>
<li><code>DUK_ENUM_ARRAY_INDICES_ONLY</code>: enumerate only array indices,
    i.e. property names of the form "0", "1", "2", etc.</li>
<li><code>DUK_ENUM_SORT_ARRAY_INDICES</code>: sort array indices by their numeric
    value, only use with <code>DUK_ENUM_ARRAY_INDICES_ONLY</code>; this is quite
    slow</li>
</ul>

<p>Without any flags, enumeration follows the Ecmascript default enumeration
semantics, as in the expression:</p>
<pre class="ecmascript-code">
for (key in obj) {
    print(key, obj[i]);
}
</pre>

<p>Once the enumerator has been created, use
<code><a href="#duk_next">duk_next()</a></code> to extract keys (or key/value
pairs) from the enumerator.</p>

=example
duk_enum(ctx, -3, DUK_ENUM_INCLUDE_NONENUMERABLE);

while (duk_next(ctx, -1 /*enum_index*/, 0 /*get_value*/)) {
    /* [ ... enum key ] */
    printf("-> key %s\n", duk_get_string(ctx, -1));
    duk_pop(ctx);
}

duk_pop(ctx);  /* pop enum object */

=tags
object
property

=seealso
duk_next