Creates an Ace Code Editor (https://ace.c9.io/)
composer require jinjie/codeeditorfield
$fields->push(CodeEditorField::create('MyCode', 'Enter Source Code Here'));
$fields->push($myCodeEditorField = CodeEditorField::create('MyCode', 'Enter Source Code Here'));
// set mode to html
$myCodeEditorField->setMode('ace/mode/html');
// or javascript
$myCodeEditorField->setMode('ace/mode/javascript');
see resources/thirdparty/ace for available modes (mode-{language}.js)