Adding jQuery function in TYPO3 backend - php

Question

I need to a custom jQuery function in my TYPO3 backend when Im opening the "Page"-view.
I added a hook for the preProcess
$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']
['cms/layout/class.tx_cms_layout.php']['tt_content_drawItem']
['tx_dashboard'] =
\vendor\dashboard\Hooks\Backend\IconCorrection::class;
And in my IconCorrection I added
public function preProcess(PageLayoutView &$parentObject, &$drawItem, &$headerContent, &$itemContent, array &$row)
{
GeneralUtility::makeInstance(PageRenderer::class)
->addRequireJsConfiguration([
'paths' => [
'iconCorrection'=>'/typo3conf/ext/dashboard/Resources/Public/JavaScript/hidePreviewIcon.js',
],
'shim' => [
'iconCorrection' => ['jquery'],
],
]);
}
}
In my hidePreviewIcon.js I have a console.log
I want something like $(".btn").hide(); but for now just testing if the js is loaded.
In my dev-tools I see that the js was loaded, but the console.log wasnt executed.
What Im missing?
And can I just using addJsFile instead of addRequireJsConfiguration
Im using TYPO3 v8.7.2
EDIT:
I added
$renderer =\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\TYPO3\CMS\Core\Page\PageRenderer::class);
$renderer->addJsFile('/typo3conf/ext/trumpf_editordashboard/Resources/Public/JavaScript/hidePreviewIcon.js', 'text/javascript', false, false, '', true, '|', false, '');
to my preProcess()function.
Now the .js was loaded and executed a console.log();
But my
$(document).ready(){$(".btn").hide();
doesnt work. I think its executed too early
EDIT 2: Did the trick:
$(function(){
$('#typo3-contentIframe').ready(function(){
console.log("loaded");
$(".btn").hide();
});
});