Bootstrap compilation takes so much time

[chetansharma10]

See this code
Why it takes more than 10 sec to compile,If it is not a right way please tell?

function compile(){
	  $cacheOptions = [
		  'cacheDir' => __DIR__.'/assets/sass-cache',
		  'prefix' => 'scssphp_',
		  'forceRefresh' =>false
	  ];
	
	try{
		$compiler = new Compiler($cacheOptions);

		// Get bootstrap SASS Input file path
		$input_path = __DIR__ . '/vendor/twbs/bootstrap/scss/bootstrap.scss';
		
		// Set Bootstrap CSS Output file path
		$output_path = __DIR__ . '/assets/css/bootstrap.css';
		
		// Get Input File Content
		$input_content = file_get_contents($input_path);
		
		// Set SASS Imports Directory
		$imports_dir_path  = __DIR__ . '/vendor/twbs/bootstrap/scss/';
		
		//  Set SCSS Imports Directory Path
		$compiler->setImportPaths($imports_dir_path);
		
		// Set Variables
		$variables = [
			'$primary' => "#110978",
		];
		
		// Replace Bootstrap Variables with Customizer Variables
		$compiler->replaceVariables($variables);

		// Get Compiled CSS
		$css_string =  $compiler->compileString($input_content);

		file_put_contents(__DIR__."/assets/bootstrap/bootstrap.min.css",$css_string->getCss());
	}
	catch(\Exception $e){
		console_log("Exception:".$e);
	}

}