Unhandled Runtime Error Error: Expected a suspended thenable. This is a bug in React. Please file an issue.

[dante01yoon]

Verify canary release

• [X] I verified that the issue exists in the latest Next.js canary release

Provide environment information

- node 16.15.0
- package.json

{ // ...
 "dependencies": {
    "@types/node": "20.1.4",
    "@types/react": "18.2.6",
    "@types/react-dom": "18.2.4",
    "autoprefixer": "10.4.14",
    "eslint": "8.40.0",
    "eslint-config-next": "13.4.2",
    "next": "13.4.2",
    "postcss": "8.4.23",
    "react": "18.2.0",
    "react-dom": "18.2.0",
    "tailwindcss": "3.3.2",
    "typescript": "5.0.4",
    "tailwindcss-animate": "^1.0.5"
  },
  "devDependencies": {
    "@typescript-eslint/eslint-plugin": "^5.57.1",
    "@typescript-eslint/parser": "^5.59.2",
    "eslint-config-prettier": "^8.8.0",
    "eslint-plugin-import": "^2.22.1",
    "eslint-plugin-jsx-a11y": "^6.4.1",
    "eslint-plugin-prettier": "^4.2.1",
    "eslint-plugin-react": "^7.31.11",
    "eslint-plugin-react-hooks": "^4.6.0",
    "eslint-plugin-react-refresh": "^0.3.4",
    "prettier": "^2.8.7",
    "@tailwindcss/typography": "^0.5.9"
  }
 // ... 
}

Which area(s) of Next.js are affected? (leave empty if unsure)

No response

Link to the code that reproduces this issue or a replay of the bug

--

To Reproduce

app/post/post.tsx

import { use } from "react"
import { getPosts } from "../api/post/getPosts"

export const Post = async () => {
  const posts = use(getPosts())

  return (
    <>
      {posts.map((post) => (
        <div key={post.id} className="bg-white p-4 rounded shadow mb-4">
          <h2 className="text-2xl font-bold mb-2">{post.title}</h2>
          <p className="text-gray-600 mb-2">
            By {post.author} | {post.date}
          </p>
          <p className="mb-4">{post.content}</p>
          <div className="bg-gray-100 p-2 rounded">
            {post.comments.map((comment, idx) => (
              <div key={comment.id} className="mb-2">
                <p className="text-gray-600 mb-1">{comment.author}</p>
                <p>{comment.text}</p>
                <div>{post.time}</div>
              </div>
            ))}
          </div>
        </div>
      ))}
    </>
  )
}

and this is where post component is used.

app/post/page.tsx

import { Suspense } from "react"
import LoadingSkeleton from "../ui/LoadingSkeleton"
import { Post } from "./post"

export default function PostPage() {
  return (
    <div className="container mx-auto py-8">
      <h1 className="text-3xl font-bold mb-6">Posts</h1>
      <div>
        this is not from data fetching: {new Date().getTime().toString()}
      </div>
      <Suspense fallback={<LoadingSkeleton />}>
        {/* @ts-expect-error Async Server Component */}
        <Post />
      </Suspense>
    </div>
  )
}

Describe the Bug

Unhandled Runtime Error
Error: Expected a suspended thenable. This is a bug in React. Please file an issue.

Call Stack
getSuspendedThenable
node_modules/next/dist/compiled/react-server-dom-webpack/cjs/react-server-dom-webpack-server.edge.development.js (697:10)
getSuspendedThenable
node_modules/next/dist/compiled/react-server-dom-webpack/cjs/react-server-dom-webpack-server.edge.development.js (1777:6)
resolveModelToJSON
node_modules/next/dist/compiled/react-server-dom-webpack/cjs/react-server-dom-webpack-server.edge.development.js (1249:13)
stringify
<anonymous>
stringify
node_modules/next/dist/compiled/react-server-dom-webpack/cjs/react-server-dom-webpack-server.edge.development.js (181:13)
processModelChunk
node_modules/next/dist/compiled/react-server-dom-webpack/cjs/react-server-dom-webpack-server.edge.development.js (2062:25)
retryTask
node_modules/next/dist/compiled/react-server-dom-webpack/cjs/react-server-dom-webpack-server.edge.development.js (2109:6)
performWork
node_modules/next/dist/compiled/react-server-dom-webpack/cjs/react-server-dom-webpack-server.edge.development.js (1544:13)
listOnTimeout
node:internal/timers (559:17)
processTimers
node:internal/timers (502:7)

Expected Behavior

when remove async keyword in component, error not thrown.

Is it intended?

wonder why this

Which browser are you using? (if relevant)

Chrome 114.0.5735.106 (arm64)

How are you deploying your application? (if relevant)

localhost - yarn dev (development mode)

[jnovak-SM2Dev]

I had a similar issue, removing async from the component fixed it for me.

[Vethavear]

But we need it to be async in order to use await.

[DanyloK0]

Same error using next-intl in Server component. if the component is not async it works.

[lshearer]

But we need it to be async in order to use await.

@Vethavear If the function is async, you can just await the promise instead of wrapping it with use.

[zsombor-guti]

@lshearer Not sure what you meant by your comment, because there are two options I see, and none of them manage to solve our issue:

1. Use use(), which is still marked as beta/experimental - wouldn't use it in prod (also, I'm not 100% sure how it works under the hood, and using Promises gives me more control, eg. run multiple requests in parallel with Promise.all)
2. Mark the server component as async and await the Promise - in which case we get the error the OP posted about.

[ehsanbahramidev]

Same error using next-intl in Server component. if the component is not async it works.

You can solve it by the below link: https://next-intl-docs.vercel.app/docs/environments/server-client-components#async-components

[SirawichDev]

Same error using next-intl in Server component. if the component is not async it works.

useTranslations not working for server component with async you might need to use getTranslations from next-intl/server instead . take a look in this link https://next-intl-docs.vercel.app/docs/environments/server-client-components#async-components

[raotaohub]

please , remove async syntax

• before

export const Post = async () => {
  const posts = use(getPosts())
  ......
}

• after

export const Post = () => {
  const posts = use(getPosts())
  ......
}

[Vethavear]

Thanks for input guys, I guess this is outdated now as we can use getTranslations from next-intl/server

[jocarrd]

Thanks

[julianosirtori]

please , remove async syntax

• before

export const Post = async () => {
  const posts = use(getPosts())
  ......
}

• after

export const Post = () => {
  const posts = use(getPosts())
  ......
}

Thanks I had the same problem and this fix worked for me

[jorgearuv]

In my case, the fix was to use const locale = await getLocale() instead.

[ulut0002]

In my case, I had the getLocale() and getTranslations() working correctly. But I had to modify the root layout.js file:

before: export default async function RootLayout({ children }) {}

after: export default function RootLayout({ children }) {}