duktape/website/api/duk_next.txt

=proto
int duk_next(duk_context *ctx, int enum_index, int get_value);

=stack
[ ... enum! ... ] -> [ ... enum! ... ]             (if enum empty; function returns zero)
[ ... enum! ... ] -> [ ... enum! ... key! ]        (if enum not empty and get_value == 0; function returns non-zero)
[ ... enum! ... ] -> [ ... enum! ... key! value! ] (if enum not empty and get_value != 0; function returns non-zero)

=summary
<p>Get the next key (and optionally value) from an enumerator created with
<tt><a href="#duk_enum">duk_enum()</a></tt>.  If the enumeration has been
exhausted, nothing is pushed to the stack and the function returns zero.
Otherwise the key is pushed to the stack, followed by the value if
<tt>get_value</tt> is non-zero, and the function returns non-zero.
</p>

<p>Note that getting the value may invoke a getter which may have arbitrary
side effects (and may throw an error).</p>

=example
while (duk_next(ctx, enum_idx, 1)) {
    printf("key=%s, value=%s\n", duk_to_string(ctx, -2), duk_to_string(ctx, -1));
    duk_pop_2(ctx);
}

=tags
object
property

=seealso
duk_enum