Callbacks return too fast

The callbacks in the gulp tasks just run when when all tasks are initiated, not when they are finished. For example for the CSS:

buildozer/lib/gulp/css.js

Lines 12 to 17 in c80fc04

    
           function css(cb) { 
        
             config.scss.forEach(scss => { 
        
               cssCompile(config.src_base_path + scss.src, config.dest_base_path + scss.dest, true); 
        
             }); 
        
             cb(); 
        
           }

We'll probably need to add all the tasks to an array and return the callback only when every task is finished.

Same issue for js and img tasks.

I tried this, with no success:

function css(cb) {
  config.scss.forEach(async scss => {
    await cssCompile({src: config.src_base_path + scss.src, dest: config.dest_base_path + scss.dest});
  });
  cb();
}

Also tried to add each cssCompile function to an array which is returned in the end, also didn't work. I haven't figured out how all these callbacks work exactly, if there's anyone who can help me out with this, feel free to contribute ❤️

Could you elaborate what this issue causes? Does it trigger a reload too fast or? And how can I reproduce?

	function css(cb) {
	config.scss.forEach(scss => {
	cssCompile(config.src_base_path + scss.src, config.dest_base_path + scss.dest, true);
	});
	cb();
	}