add some unit test

README.md

@@ -109,14 +109,14 @@ const anAtom = atom(0);
 
 const Header = () => {
   const num = useAtomValueWithSchedule(anAtom, {
-    priority: LowPriority,
+    priority: LOW_PRIORITY,
   });
   return <div className="header">Header-{num}</div>;
 };
 
 const Footer = () => {
   const num = useAtomValueWithSchedule(anAtom, {
-    priority: LowPriority,
+    priority: LOW_PRIORITY,
   });
   return <div className="footer">Footer-{num}</div>;
 };
@@ -128,7 +128,7 @@ const Sidebar = () => {
 
 const Content = () => {
   const [num, setNum] = useAtomWithSchedule(anAtom, {
-    priority: ImmediatePriority,
+    priority: IMMEDIATE_PRIORITY,
   });
   return (
     <div className="content">

__tests__/basic.test.tsx

@@ -0,0 +1,56 @@
+import { atom } from 'jotai'
+import { render, waitFor } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { useEffect, useRef } from 'react'
+
+import { useAtomValueWithSchedule, useSetAtomWithSchedule } from '../src'
+
+const useCommitCount = () => {
+  const commitCountRef = useRef(1)
+  useEffect(() => {
+    commitCountRef.current += 1
+  })
+  return commitCountRef.current
+}
+
+describe('the same behavior as jotai if the `priority` field is not passed', () => {
+  it('trigger state updates correctly', async () => {
+    const anAtom = atom(0)
+    function Control() {
+      const dispatch = useSetAtomWithSchedule(anAtom)
+      return (
+        <>
+          <button type="button" onClick={() => dispatch((num) => num + 1)}>
+            button
+          </button>
+          <div>Control commits: {useCommitCount()}</div>
+        </>
+      )
+    }
+    function Display() {
+      const num = useAtomValueWithSchedule(anAtom)
+      return (
+        <>
+          <div>number: {num}</div>
+          <div>Display commits: {useCommitCount()}</div>
+        </>
+      )
+    }
+    function App() {
+      return (
+        <>
+          <Display />
+          <Control />
+        </>
+      )
+    }
+    const { findByText, getByText } = render(<App />)
+    await findByText('number: 0')
+    await userEvent.click(getByText('button'))
+    await waitFor(() => {
+      findByText('number: 1')
+      findByText('Display commits: 1')
+      findByText('Control commits: 2')
+    })
+  })
+})

__tests__/priority.test.tsx

@@ -0,0 +1,67 @@
+import { atom } from 'jotai'
+import { render, waitFor } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+
+import {
+  IMMEDIATE_PRIORITY,
+  LOW_PRIORITY,
+  NORMAL_PRIORITY,
+  useAtomValueWithSchedule,
+  useSetAtomWithSchedule,
+} from '../src'
+
+it('batching rendering if we pass different `priority`', async () => {
+  const anAtom = atom(0)
+  function ImmediatePriorityCpn() {
+    const num = useAtomValueWithSchedule(anAtom, {
+      priority: IMMEDIATE_PRIORITY,
+    })
+    return <div>number of ImmediatePriorityCpn: {num}</div>
+  }
+  function NormalPriorityCpn() {
+    const num = useAtomValueWithSchedule(anAtom, {
+      priority: NORMAL_PRIORITY,
+    })
+    return <div>number of NormalPriorityCpn: {num}</div>
+  }
+  function LowPriorityCpn() {
+    const num = useAtomValueWithSchedule(anAtom, {
+      priority: LOW_PRIORITY,
+    })
+    return <div>number of LowPriorityCpn: {num}</div>
+  }
+  function App() {
+    const dispatch = useSetAtomWithSchedule(anAtom)
+    return (
+      <>
+        <ImmediatePriorityCpn />
+        <NormalPriorityCpn />
+        <LowPriorityCpn />
+        <button type="button" onClick={() => dispatch((num) => num + 1)}>
+          button
+        </button>
+      </>
+    )
+  }
+  const { findByText, getByText } = render(<App />)
+
+  await userEvent.click(getByText('button'))
+
+  await waitFor(() => {
+    findByText('number of ImmediatePriorityCpn: 1')
+    findByText('number of NormalPriorityCpn: 0')
+    findByText('number of LowPriorityCpn: 0')
+  })
+
+  await waitFor(() => {
+    findByText('number of ImmediatePriorityCpn: 1')
+    findByText('number of NormalPriorityCpn: 1')
+    findByText('number of LowPriorityCpn: 0')
+  })
+
+  await waitFor(() => {
+    findByText('number of ImmediatePriorityCpn: 1')
+    findByText('number of NormalPriorityCpn: 1')
+    findByText('number of LowPriorityCpn: 1')
+  })
+})

src/useSetAtomWithSchedule.ts

@@ -22,9 +22,7 @@ export function useSetAtomWithSchedule<Value, Args extends unknown[], Result>(
   const store = useStore(options)
   const setAtom = useCallback(
     (...args: Args) => {
-      // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-      // @ts-ignore
-      if (import.meta.env?.MODE !== 'production' && !('write' in atom)) {
+      if (!('write' in atom)) {
         // useAtom can pass non writable atom with wrong type assertion,
         // so we should check here.
         throw new Error('not writable atom')

src/workLoop.ts

@@ -47,12 +47,18 @@ function handleNextBatch() {
   }
 }
 
-const channel = new MessageChannel()
-const port = channel.port2
-channel.port1.onmessage = handleNextBatch
-
-export const enqueueWorkExecution = () => {
-  port.postMessage(null)
+let enqueueWorkExecution: () => void
+if (typeof MessageChannel !== 'undefined') {
+  const channel = new MessageChannel()
+  const port = channel.port2
+  channel.port1.onmessage = handleNextBatch
+  enqueueWorkExecution = (): void => {
+    port.postMessage(null)
+  }
+} else {
+  enqueueWorkExecution = (): void => {
+    setTimeout(handleNextBatch, 0)
+  }
 }
 
 export const initiateWorkLoop = () => {

tsconfig.json

@@ -17,5 +17,6 @@
       "jotai-scheduler": ["./src/index.ts"]
     }
   },
+  "include": ["src", "__tests__"],
   "exclude": ["dist", "examples", "jotai"]
 }