This is an odd question. I couldn't find any resource relating to developing a react app and integrating it into the online store(not the merchant page).
https://shopify.dev/apps/getting-started/create, this link only discusses developing an app and integrating it into the Shopify merchant page, not on the online store.
I have gone through the documentation on the above link but could not find anything relevant.
Also, check this link https://shopify.dev/apps/online-store, but creating theme extensions is not what I want as I want to develop a full-fledged application like https://apps.shopify.com/tolstoy
Can you guys point me to the right resource?
thanks
Shopify is HTML, CSS and Javascript. There is nothing stopping you from making the merchant end of things ANYTHING you want. Get yourslf a Storefront API token and you're good to go.
As for a lack of resources? HTML, CSS and Javascript are 90% of your journey covered by a bazillion resources including StackOverflow. Shopify documents Storefront API fine too. What more could you ask for?