How To Add Javascript File From Typo3 Extension

Add Below line in your typo3 extension controller file.

$GLOBALS['TSFE']->getPageRenderer()->addJsFooterFile
(\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::siteRelPath('extension_key') . 'Resources/Public/
javascript/yourjsfile.js',
$compress = FALSE,
$forceOnTop = FALSE,
$allWrap = '');

-- Change Extension key and your JS file path.