Improved loading handling

front/src/hooks/useFetch.ts

@@ -3,29 +3,44 @@ import { useEffect, useState } from 'react'
 import useSend from './useSend'
 
 type UseFetchShared = {
-    loading: boolean,
     abort?: () => void,
     refetch: () => void,
 }
 
 type UseFetchSucced<T> = {
-    error: null,
     data: T,
+    loading: false,
+    error: null,
+} & UseFetchShared
+
+type UseFetchLoading = {
+    data: undefined,
+    loading: true,
+    error: null,
 } & UseFetchShared
 
 type UseFetchErrored = {
-    error: string,
     data: undefined,
+    loading: false,
+    error: string,
 } & UseFetchShared
 
-type UseFetchReturn<T> = UseFetchSucced<T> | UseFetchErrored
+type UseFetchReturn<T> = UseFetchSucced<T> | UseFetchLoading | UseFetchErrored
 
 const gotError = <T>(res: UseFetchReturn<T>): res is UseFetchErrored => (
     typeof res.error === 'string'
 )
 
-const fallbackError = <T>(res: UseFetchReturn<T>) => (
-    gotError(res) ? res.error : res.data
+function fallbackError<T>(res: UseFetchSucced<T> | UseFetchErrored): T | string
+function fallbackError<T>(res: UseFetchReturn<T>): T | string | undefined
+function fallbackError<T>(res: UseFetchReturn<T>): T | string | undefined {
+    return (
+        gotError(res) ? res.error : res.data
+    )
+}
+
+const gotResponse = <T>(res: UseFetchReturn<T>): res is UseFetchSucced<T> | UseFetchErrored => (
+    !res.loading
 )
 
 function useFetch<R, T extends NonNullable<unknown>>(
@@ -59,13 +74,28 @@ function useFetch<R, T extends NonNullable<unknown>>(
 
     useEffect(refetch, [doSend])
 
+    if (loading === true) {
+        return {
+            data: undefined,
+            loading,
+            error: null,
+            refetch,
+        }
+    }
+
+    if (error !== null) {
+        return {
+            data: undefined,
+            loading,
+            error,
+            refetch,
+        }
+    }
+
     return {
-        ...(
-            error === null ? ({
-                data: data!, error: null,
-            }) : ({ data: undefined, error })
-        ),
+        data: data!,
         loading,
+        error,
         refetch,
     }
 }
@@ -74,4 +104,4 @@ export type { UseFetchReturn }
 
 export default useFetch
 
-export { gotError, fallbackError }
+export { gotError, gotResponse, fallbackError }