I want to track the actions taken by the logged-in user in Shopify admin.
If a shop has multiple staff with admin access, how can I get the information of which staff/user is currently logged in?
It can be either via API or from JS.
I don't think there's a log of actions by staff in Shopify Admin. You can see when staff was last logged in (Shopify Admin > Settings > Accounts), but you won't be able to track what they are doing.
You can see some activity through /admin/activity but it's very limited.
However, there are available apps that can track those for you. You can checkout Staffy or Logify.