Typings cleanup and improvements

Appease linter

(cherry picked from commit b2c43fb2a67965d68d3d35b72302b0cddb5aca23)
(cherry picked from commit 3b5e83670b844cf7c20bf7d744d9fbc96fde6902)

Closes #3516
Closes #3510
Closes #2778

frontend/src/Store/thunks.ts

@@ -0,0 +1,39 @@
+import { Dispatch } from 'redux';
+import AppState from 'App/State/AppState';
+
+type GetState = () => AppState;
+type Thunk = (
+  getState: GetState,
+  identityFn: never,
+  dispatch: Dispatch
+) => unknown;
+
+const thunks: Record<string, Thunk> = {};
+
+function identity<T, TResult>(payload: T): TResult {
+  return payload as unknown as TResult;
+}
+
+export function createThunk(type: string, identityFunction = identity) {
+  return function <T>(payload?: T) {
+    return function (dispatch: Dispatch, getState: GetState) {
+      const thunk = thunks[type];
+
+      if (thunk) {
+        const finalPayload = payload ?? {};
+
+        return thunk(getState, identityFunction(finalPayload), dispatch);
+      }
+
+      throw Error(`Thunk handler has not been registered for ${type}`);
+    };
+  };
+}
+
+export function handleThunks(handlers: Record<string, Thunk>) {
+  const types = Object.keys(handlers);
+
+  types.forEach((type) => {
+    thunks[type] = handlers[type];
+  });
+}