create-react-app: Hanging at 'Files successfully emitted, waiting for typecheck results...'

I’m getting the same issue, tried everything in here, nothing fixes it apart from reverting which isn’t ideal.

Revert to 3.4.0 solve this issue for me

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Can confirm this is happening as well on a fresh ejected project. It hangs on that message, but after you change a file to trigger a recompile, it stops hanging until you restart the dev server.

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I’ve now tried with a fresh and empty CRA and i can confirm that for me it does not happen, exact package versions are listed below if you’re interested.

However i was using workerize-loader to use a web worker to convert images to base-64 strings in the background.

The import statement needed to use the worker was using a custom format:

import createWorker, {
  Workerized
} from "workerize-loader!./my-worker-file.worker";

And this worked because i had a custom typings file:

declare module "workerize-loader!*" {
  type AnyFunction = (...args: any[]) => any;
  type Async<F extends AnyFunction> = (
    ...args: Parameters<F>
  ) => Promise<ReturnType<F>>;

  export type Workerized<T> = Worker &
    { [K in keyof T]: T[K] extends AnyFunction ? Async<T[K]> : never };

  function createInstance<T>(): Workerized<T>;
  export = createInstance;
}

The import statement above also needed a // eslint-disable-next-line, when i removed it i saw that the error was stating that you shouldn’t use custom imports to modify the webpack build. This was build by my friend so i did not know what the effects were.

As soon as i added these files and used them in the new fresh CRA project i got locked at the message mentioned in the issue title.

It’s not likely that you’re facing this exact issue, but maybe you have custom typing somewhere that is causing this. I thought I’d put it here for future readers.

This will probably lead to us ejecting from CRA instead, since we have a couple of things that needs it.

Here’s our exact package versions, since i did not get the error without the workerize-loader package, maybe you’d like to try the version of react-scripts we’re using. Beware that we are using slightly older versions of the packages since we’re hunting problems of our own with this project:

{
  "name": "my-app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@babel/plugin-proposal-optional-chaining": "7.7.5",
    "@mdi/js": "4.8.95",
    "@mdi/react": "1.2.1",
    "@types/jest": "24.0.17",
    "@types/node": "12.7.1",
    "@types/react": "16.9.1",
    "@types/react-dom": "16.8.5",
    "file-saver": "2.0.2",
    "moment": "2.24.0",
    "react": "16.12.0",
    "react-dom": "16.12.0",
    "react-scripts": "3.4.0",
    "typescript": "3.7.3",
    "workerize-loader": "1.1.0"
  },
  "devDependencies": {
    "@types/file-saver": "2.0.1",
    "eslint": "6.8.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "babel": {
    "plugins": [
      "@babel/plugin-proposal-optional-chaining"
    ]
  }
}

I’m seeing this same issue just pop up with the dev server. Deleted node_modules and re-installed, same result. If I let the process hang for long enough it fails with JavaScript heap out of memory.

FYI I have analyzed this issue a little bit and opened #10871 to include a reproduction attempt. I’m pretty sure that it involves a race condition, so it is unlikely to reproduce the problem with 100%.

Even better:

I did a yarn eject and changed in webpack.config.js this line to useTypescriptIncrementalApi: false, and it works again.

Will roll back and edit inside the node_modules folder for now.

Hey guys, I solved this issue with yarn.lock (or package-lock)

1. just use previous (working) version of lock file
2. clean project with this script:

rm -rf node_modules
rm -f package-lock.json
rm -f yarn.lock
npm cache clean --force

1. yarn install
2. done !

This issue began for me in one of my projects after installing typescript-plugin-css-modules. I removed this and this issue has ceased since. I do not know if this information is helpful, but I thought I would add it.

Self quote from here:

As far as I understood it, it’s due to Typescripts incremental API, which is invoked by fork-ts-checker-webpack-plugin. They have an update, but it isn’t part of CRA yet.

https://github.com/TypeStrong/fork-ts-checker-webpack-plugin/issues/463

My personal solution is to opt out of the incremental API by patching CRA Webpack config.

https://github.com/pixelkritzel/savages/blob/master/patchWebpackConfig.js

I’ve now tried with a fresh and empty CRA and i can confirm that for me it does not happen, exact package versions are listed below if you’re interested.

However i was using workerize-loader to use a web worker to convert images to base-64 strings in the background.

The import statement needed to use the worker was using a custom format:

import createWorker, {
  Workerized
} from "workerize-loader!./my-worker-file.worker";

And this worked because i had a custom typings file:

declare module "workerize-loader!*" {
  type AnyFunction = (...args: any[]) => any;
  type Async<F extends AnyFunction> = (
    ...args: Parameters<F>
  ) => Promise<ReturnType<F>>;

  export type Workerized<T> = Worker &
    { [K in keyof T]: T[K] extends AnyFunction ? Async<T[K]> : never };

  function createInstance<T>(): Workerized<T>;
  export = createInstance;
}

The import statement above also needed a // eslint-disable-next-line, when i removed it i saw that the error was stating that you shouldn’t use custom imports to modify the webpack build. This was build by my friend so i did not know what the effects were.

As soon as i added these files and used them in the new fresh CRA project i got locked at the message mentioned in the issue title.

It’s not likely that you’re facing this exact issue, but maybe you have custom typing somewhere that is causing this. I thought I’d put it here for future readers.

This will probably lead to us ejecting from CRA instead, since we have a couple of things that needs it.

Here’s our exact package versions, since i did not get the error without the workerize-loader package, maybe you’d like to try the version of react-scripts we’re using. Beware that we are using slightly older versions of the packages since we’re hunting problems of our own with this project:

{
  "name": "my-app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@babel/plugin-proposal-optional-chaining": "7.7.5",
    "@mdi/js": "4.8.95",
    "@mdi/react": "1.2.1",
    "@types/jest": "24.0.17",
    "@types/node": "12.7.1",
    "@types/react": "16.9.1",
    "@types/react-dom": "16.8.5",
    "file-saver": "2.0.2",
    "moment": "2.24.0",
    "react": "16.12.0",
    "react-dom": "16.12.0",
    "react-scripts": "3.4.0",
    "typescript": "3.7.3",
    "workerize-loader": "1.1.0"
  },
  "devDependencies": {
    "@types/file-saver": "2.0.1",
    "eslint": "6.8.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "babel": {
    "plugins": [
      "@babel/plugin-proposal-optional-chaining"
    ]
  }
}

I have a very similar issue I’m experiencing for the last couple of weeks - I was sure it’s related to me importing babel/rollup in some areas of the code.

My setup is very similar with workerize loader and typescript - only that I have partial typescript throughout the app and the part loading the loader is plain jsx - so I never noticed it’s related.

On top of that I’m loading the worker file twice, once as a worker and once as a regular module.

Removing the workerize loader import resolved my issue! Now simply to rewrite the API between worker and main thread.

Same here.

But if I run yarn tsc --noEmit it’s done in a second

I’m currently experiencing the same issue with the dev server getting stuck on Files successfully emitted, waiting for typecheck results....

I tried the steps @sandorvasas noted above and it is still not fixing the issue for me. @sandorvasas are you using any web workers with workerize perhaps?