Returns constants matching an error level

errorLevelToConstants.php

<?php

/**
 * Examples:
 *
 * errorLevelToConstants(E_WARNING) => ['E_WARNING', 'E_ALL']
 * errorLevelToConstants(3) => ['E_ERROR', 'E_WARNING', 'E_ALL']
 *
 * @return string[]
 */
function errorLevelToConstants(int $level): array
{
    $constants = [];

    foreach (get_defined_constants() as $constant => $value) {
        if (str_starts_with($constant, 'E_')) {
            if (($level & $value) !== 0) {
                $constants[] = $constant;
            }
        }
    }

    return $constants;
}