One simple place to start with

If you click on library menu or go to url http://github.planetfarms.io:3000/library
On page load of library it trigger action to fetch library resources

Line 41 in ee470b4

if (!search) dispatch(listResources('', pageNumber))

Which will call action

Line 15 in ee470b4

export const listResources = ({ sort, pageNumber }) => async (dispatch) => {

Action which fetch the resources of library and will intiate state of loading by reducer

Line 17 in ee470b4

dispatch({ type: RESOURCE_LIST_REQUEST })

After data returned will call reducer

Line 22 in ee470b4

dispatch({ type: RESOURCE_LIST_SUCCESS, payload: data })

All these reducers are under

Line 14 in ee470b4

export const resourceListReducer = (state = { resources: [] }, action) => {

payload returned by reducers in action will be grabbed under

const resourceList = useSelector((state) => state.listResources)

Here we can get loading and use that value somewhere inside

Line 56 in ee470b4

To display or hide loading icon
For loader you can use some package like
https://www.npmjs.com/package/react-loader-spinner

loading spinner while requesting data in backend #336

Description