How to Maintain Environment and Update Changes on the Shopify Storefront in Development Mode ???

[codeconfig-dev]

When working on a Shopify app extension,  In Extension local JS and CSS and liquid file change but the store fronted don't update properly !! why ?  How you maintain the development env or production env in building on extension ? 

I'm new learning on shopify app &&& extension working currently facing this issue !!  How to solution development change update storefront !! 

   Need to solution !! 

         ## development change reflect the store fronted update properly !! 
         ## How  you maintain development mood and production mood extension working env !!