feat(loaders): the initial value of error is now null

BREAKING CHANGE: the initial value of undefined was a mistake
(differently from data which does start as undefined). The initial state
of a loader should be pending, data: undefined, and error: null

Author: posva

src/data-loaders/defineColadaLoader.ts

@@ -168,7 +168,7 @@ export function defineColadaLoader<Data>(
         // force the type to match
         data: shallowRef<Data | undefined>(),
         isLoading: shallowRef(false),
-        error: shallowRef<any>(),
+        error: shallowRef<unknown>(null),
         to,
 
         options,

src/data-loaders/defineLoader.ts

@@ -141,7 +141,7 @@ export function defineBasicLoader<Data>(
         // force the type to match
         data: shallowRef<Data | undefined>(),
         isLoading: shallowRef(false),
-        error: shallowRef<ErrorDefault | null>(),
+        error: shallowRef<ErrorDefault | null>(null),
         to,
 
         options,

tests/data-loaders/tester.ts

@@ -1408,10 +1408,10 @@ export function testDefineLoader<Context = void>(
       await p
       const { data: one, error: e1 } = app.runWithContext(() => l1.loader())
       const { data: two, error: e2 } = app.runWithContext(() => l2.loader())
-      expect(one.value).toBeUndefined()
-      expect(e1.value).toBeUndefined()
-      expect(two.value).toBeUndefined()
-      expect(e2.value).toBeUndefined()
+      expect(one.value).toBe(undefined)
+      expect(e1.value).toBe(null)
+      expect(two.value).toBe(undefined)
+      expect(e2.value).toBe(null)
     }
   )