Remove trailing whitespace from an input string (multiline).

removeTrailingWhiltespace.php

function removeTrailingWhitespace(string $string) : string
{
    return preg_replace('/[ \t]+(\r?)$/m', '$1', $string);
}

// PHPUnit testcase for method
// public function testTestInternalRemoveTrailingWhitespace()
// {
//     $this->assertSame(
//         "\n	some\r\n string\n\n\r\nto remove trailing\n whitespace from.\n\n",
//         removeTrailingWhitespace("\n	some  \r\n string\n  \n   \r\nto remove trailing \n whitespace from.	\n\n")
//     );
// }