Safe area, Multi Resolution Support in Web

Hello,

I’m currently working on a game which has to be integrated with react native. Thus, I will be using the cocos-2D-v3.13.js file as the engine.
I would have to support varied number of mobile devices and tablets. But won’t be targeting desktops.

I really need a pointer or two about multi resolution support.
I went through quite a number of posts about the same, but some of the links were dead. I have been working on corona-sdk for a while and I have clear idea about safe areas and multi-resolution support.
But my question is how do I do it in cocos-2D-js.

Are safe areas not a concern if I’m using canvas. How do I go about calling for prefixed assets such as 1x - normal sized assets. 2x - high resolution assets. 4x- retina resolution assets.

Please guide me in this regard
Thank you