drop optional priority

src/vanilla/store.ts

@@ -93,7 +93,7 @@ export type AtomState<Value = AnyValue> = {
    */
   readonly d: Map<AnyAtom, number>
   /** Set of priority listeners to run when the atom value changes. */
-  readonly l: Set<readonly [listener: BatchListener, priority?: BatchPriority]>
+  readonly l: Set<readonly [listener: BatchListener, priority: BatchPriority]>
   /**
    * Set of atoms with pending promise that depend on the atom.
    *
@@ -203,7 +203,7 @@ const registerBatchAtom = (
   if (!batch.D.has(atom)) {
     batch.D.set(atom, new Set())
     const scheduleListeners = () => {
-      for (const [listener, priority = 'M'] of atomState.l || []) {
+      for (const [listener, priority] of atomState.l) {
         addBatchFunc(batch, listener, priority)
       }
     }
@@ -692,7 +692,7 @@ const buildStore = (...storeArgs: StoreArgs): Store => {
       // unmount self
       const onUnmount = atomState.m.u
       if (onUnmount) {
-        addBatchFunc(batch, () => onUnmount(batch), 'L')
+        addBatchFunc(batch, onUnmount, 'L')
       }
       delete atomState.m
       // unmount dependencies
@@ -709,14 +709,14 @@ const buildStore = (...storeArgs: StoreArgs): Store => {
     const batch = createBatch()
     const atomState = getAtomState(atom)
     const mounted = mountAtom(batch, atom, atomState)
-    const priorityListener = [() => listener()] as const
-    atomState.l.add(priorityListener)
+    const priorityListener = [() => listener(), 'M'] as const
     ++mounted.l
+    atomState.l.add(priorityListener)
     flushBatch(batch)
     return () => {
       const batch = createBatch()
-      atomState.l.delete(priorityListener)
       --mounted.l
+      atomState.l.delete(priorityListener)
       unmountAtom(batch, atom, atomState)
       flushBatch(batch)
     }

tests/setup.ts

@@ -1,11 +1,13 @@
 import '@testing-library/jest-dom/vitest'
-import { expect } from 'vitest'
+import { expect, vi } from 'vitest'
+
+type MockFunction = ReturnType<typeof vi.fn>
 
 expect.extend({
-  toHaveBeenCalledBefore(received, expected) {
+  toHaveBeenCalledBefore(received: MockFunction, expected: MockFunction) {
     const pass =
-      received.mock.invocationCallOrder[0] <
-      expected.mock.invocationCallOrder[0]
+      received.mock.invocationCallOrder[0]! <
+      expected.mock.invocationCallOrder[0]!
     return {
       pass,
       message: () =>

tests/vanilla/effect.test.ts

@@ -108,9 +108,9 @@ function atomSyncEffect(effect: Effect) {
             : null
       }
       const priority: BatchPriority = 'H'
-      const entry = [batchListener, priority] as const
-      atomState.l.add(entry)
-      return () => atomState.l.delete(entry)
+      const priorityListener = [batchListener, priority] as const
+      atomState.l.add(priorityListener)
+      return () => atomState.l.delete(priorityListener)
     }
   }
   const effectAtom = Object.assign(

tests/vanilla/store.test.tsx

@@ -1108,11 +1108,9 @@ it('should call the batch listener with batch and respect the priority', () => {
   const a = atom(0)
   const highPriorityBatchListener = vi.fn() as BatchListener
   const mediumPriorityBatchListener = vi.fn() as BatchListener
-  const defaultPriorityBatchListener = vi.fn() as BatchListener // medium
   const lowPriorityBatchListener = vi.fn() as BatchListener
   a.INTERNAL_onInit = (_store, atomState) => {
     atomState.l.add([lowPriorityBatchListener, 'L'])
-    atomState.l.add([defaultPriorityBatchListener])
     atomState.l.add([highPriorityBatchListener, 'H'])
     atomState.l.add([mediumPriorityBatchListener, 'M'])
   }
@@ -1122,16 +1120,12 @@ it('should call the batch listener with batch and respect the priority', () => {
   expect(highPriorityBatchListener).toHaveBeenCalledWith(mockBatch)
   expect(mediumPriorityBatchListener).toHaveBeenCalledWith(mockBatch)
   expect(lowPriorityBatchListener).toHaveBeenCalledWith(mockBatch)
-  // @ts-expect-error toHaveBeenCalledBefore is a custom matcher
-  expect(highPriorityBatchListener).toHaveBeenCalledBefore(
+  // eslint-disable-next-line @vitest/valid-expect
+  ;(expect(highPriorityBatchListener) as any).toHaveBeenCalledBefore(
     mediumPriorityBatchListener,
   )
-  // @ts-expect-error toHaveBeenCalledBefore is a custom matcher
-  expect(mediumPriorityBatchListener).toHaveBeenCalledBefore(
-    lowPriorityBatchListener,
-  )
-  // @ts-expect-error toHaveBeenCalledBefore is a custom matcher
-  expect(defaultPriorityBatchListener).toHaveBeenCalledBefore(
+  // eslint-disable-next-line @vitest/valid-expect
+  ;(expect(mediumPriorityBatchListener) as any).toHaveBeenCalledBefore(
     lowPriorityBatchListener,
   )
 })