Enable catcher with different types

src/composable/composable.ts

@@ -198,18 +198,18 @@ function map<T extends Composable, R>(
  *  originalInput.id * -1
  * ))
  */
-function catchError<T extends Composable, R>(
-  fn: T,
+function catchError<T extends Fn, R>(
+  fn: Composable<T>,
   catcher: (
     err: Omit<Failure, 'success'>,
     ...originalInput: Parameters<T>
-  ) => UnpackResult<ReturnType<T>>,
+  ) => R,
 ) {
-  return (async (...args) => {
+  return (async (...args: Parameters<T>) => {
     const res = await fn(...args)
     if (res.success) return success(res.data)
     return composable(catcher)(res, ...(args as any))
-  }) as T
+  }) as Composable<(...args: Parameters<T>) => ReturnType<T> | R>
 }
 
 /**

src/composable/index.test.ts

@@ -384,7 +384,23 @@ describe('mapError', () => {
 })
 
 describe('catchError', () => {
-  it('receives an error as input to another composable', async () => {
+  it('changes the type to accomodate catcher return type', async () => {
+    const fn = catchError(faultyAdd, () => null)
+    const res = await fn(1, 2)
+
+    type _FN = Expect<
+      Equal<typeof fn, Composable<(a: number, b: number) => number | null>>
+    >
+    type _R = Expect<Equal<typeof res, Result<number | null>>>
+
+    assertEquals(res, {
+      success: true,
+      data: null,
+      errors: [],
+    })
+  })
+
+  it('receives an error as input to another function and returns a new composable', async () => {
     const fn = catchError(faultyAdd, (_error, a, b) => a + b)
     const res = await fn(1, 2)