7

I got a sudden error that the module 'fs' is unable to resolve. But I have not used this module nor changed anything. My App suddenly returns this error while starting.

error: bundling failed: Error: Unable to resolve module fs from /Path/to/Project/node_modules/handlebars/lib/index.js: Module fs does not exist in the Haste module map

This might be related to https://github.com/facebook/react-native/issues/4968 To resolve try the following:

  1. Clear watchman watches: watchman watch-del-all.
  2. Delete the node_modules folder: rm -rf node_modules && npm install.
  3. Reset Metro Bundler cache: rm -rf /tmp/metro-bundler-cache-* or npm start -- --reset-cache.
  4. Remove haste cache: rm -rf /tmp/haste-map-react-native-packager-*.

I already tried the four steps to resolve, several times but nothing helped. Any ideas what could be wrong?

Pavindu
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dav1904
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7 Answers7

23

For me, the issue was that VSCode had inserted some imports at the top of one of my js files. Very odd. These were the lines:

import { tsConstructorType } from '@babel/types';
import { logger } from 'handlebars';
Dan Kronholm
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  • Same! The line was: import {formatResultsErrors} from 'jest-message-util'; – Hugo Nov 01 '19 at 20:25
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    You saved my day! my line was import NodeEnvironment from 'jest-environment-node'; Don't have any idea how vscode added that, quite scary – lamazing Nov 14 '19 at 18:51
  • Incredible. I spent half a day wondering why my application was stalling. Thank you! – gbones Nov 21 '19 at 15:43
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    Same thing with VSCode automatically importing this line: ```import { format } from 'prettier';``` – Olivier Apr 28 '20 at 14:41
6

One of my node modules is depending on react-native-dotenv, but its code was using old import like import {} from 'react-native-dotenv'. But latest version of dotenv is using import {} from '@env'. Fixing this import in the module resolved the problem.

Martin Atanasov
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0

Usually you can fix these surprise errors by clearing your cache. Run $ expo start --clear.

Harry Moreno
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0

I had this error because I was trying to use dotenv when I should have been using one of these react-native specific packages. Check that all your installed packages are compatible with react native.

Andrew
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0

I had exactly this issue. Visual Studio Code users, autocomplete will sometimes auto-import modules you have no need for at the top of your file without you noticing. Running git diff revealed the following lines I had no memory of every writing at the top of a file I'd worked on:

+import { clearConfigCache } from 'prettier';
+import { createIconSetFromFontello } from 'react-native-vector-icons';

How to avoid:

Run git diff and read every single line that follows. The offenders will usually turn up.

Dane_duPlessis
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0

If you are importing a module (a functional/class component from another file) in expo react native, be sure to mention "./" in the assets array of the rnpm object in the package.json file like this:

"rnpm": {
    "assets": [
      "./"
    ]
  }

Do not try to install "fs" module separately, it would give more errors.

Lakshya Monga
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0

my auto-suggestion accidentally imported this in my file which caused the same problem.

import { status } from "express/lib/response";

I removed and it worked. try to find something in import that should not be there like from backend imports.

M1NT
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