Online PHP editor | refs for KDWtR

<?php function hasValues(iterable &$value): bool { if (is_array($value)) { return (bool)$value; } if ($value instanceof \Iterator) { return $value->valid(); } $value = $value->getIterator(); return hasValues($value); } $weakMap = new WeakMap(); $x = new stdClass(); $y = new stdClass(); $weakMap[$x] = 'x'; $weakMap[$y] = 'y'; $data = [ [1, 2, 3], [], (fn () => yield from [1, 2, 3])(), (fn () => yield from [])(), new ArrayIterator([1, 2, 3]), new ArrayIterator([]), $weakMap, new WeakMap(), new RecursiveIteratorIterator(new RecursiveDirectoryIterator('/tmp', RecursiveDirectoryIterator::SKIP_DOTS)), ]; foreach ($data as $d) { print_r([ 'value' => $d, 'hasValues' => var_export($hasValues = hasValues($d), true), // Once a generator is checked and does not have any values we can't attempt to iterate it anymore. 'values' => $hasValues ? (is_array($d) ? $d : iterator_to_array($d, false)) : 'null', ]); }