Expo : cannot find a module LogReporter

Question

I have created a React Native Project and I was trying to open that project in Expo XDE. It throws the following error:

Cannot find module ...\node_modules\expo\tools\LogReporter

Firstly I created a React Native project by cloning a KitchenSink Project. Link:

NativeBase-KitchenSink

When I started the project by issuing series of commands inside the project root directory:

npm install and then expo start

I saw that the app.json was also not proper, which was the following:

{
  "name": "NativebaseKitchenSink",
  "displayName": "NativebaseKitchenSink"
}

After issuing expo start react-native reported that the app.json is not to be found in the current directory.

[17:05:08] Starting project at D:\Projects\ReactNativeProjects\AwesomeProject [17:05:10] Error: Missing app.json. See https://docs.expo.io/ [17:05:10] Couldn't start project. Please fix the errors and restart the project. [17:05:10] Error: Couldn't start project. Please fix the errors and restart the project. at C:\xdl@51.4.0\src\Project.js:1565:11 at Generator.next () at step (C:\Users\hp\AppData\Roaming\npm\node_modules\expo-cli\node_modules\xdl\build\Project.js:2033:191) at C:\Users\hp\AppData\Roaming\npm\node_modules\expo-cli\node_modules\xdl\build\Project.js:2033:361 at process._tickCallback (internal/process/next_tick.js:68:7)

I changed app.json to:

{
  "expo": {
    "name": "AwesomeProject",
    "description": "A Kitchen Sink project.",
    "slug": "AwesomeProject",
    "privacy": "public",
    "sdkVersion": "30.0.0",
    "platforms": [
      "ios",
      "android"
    ],
    "ios": {
      "supportsTablet": true
    },
    "android": {
      "package": "com.abhsax.first"
    },
    "version": "1.0.0",
    "orientation": "portrait",
    "icon": "./assets/logo.png",
    "splash": {
      "image": "./assets/splashscreen.png",
      "resizeMode": "contain",
      "backgroundColor": "#ffffff"
    },
    "updates": {
      "fallbackToCacheTimeout": 0
    },
    "assetBundlePatterns": [
      "**/*"
    ]
  }
}

There were some updates in the project when I issued npm install again. Then I issued:

expo start

This error came:

(node:2044) UnhandledPromiseRejectionWarning: Error: Cannot find module 'D:\Projects\ReactNativeProjects\AwesomeProject\node_modules\expo\tools\LogReporter'

Why am I getting this error, and how can I fix it?

Answer 1

check your package.json if it contains all needed dependencies and run npm install in the home directory of the project

if a package is missing you can add it with

npm install <package_name> --save

if you are using yarn run:

yarn add expo

Answer 2

I did:

yarn add expo

and it worked for me =)

Answer 3

See docs:

introducing-button-yarn-and-a-public-roadmap

and

npm-vs-yarn-in-react-native

These documents say that since the project configured using Yarn, you have to follow Yarn way. [Note: There is a file yarn.lock inside the root directory of the project, you have posted]

Therefore such projects are dealt by following the instructions in the documentation.

Please see How do I create a React Native project using Yarn? to actually create a react-native project using Yarn.

And please be sure to remove node_modules folder and issue command npm install before adding react native CLI using yarn. You have to remove package-lock.json from your project root. This will be to prevent mixing different package managers : npm and yarn.

Instead, it will be a good idea not to use npm, and in order to generate node_modules, just issue command:

yarn

Last link recommends to install every package you need using yarn, and not to use any other package manager:

yarn global add react-native-cli

to add react-native:

yarn add react-native

to add missing packages:

yarn add react-base --save

and to install expo using yarn:

yarn add expo

install expo-cli

yarn add expo-cli

It is possible that you can do without Expo. Just focus on react-native and yarn.

Generate android and ios folders:

react-native eject

Start yarn:

yarn start

run build of your choice, and make sure the SDKs are installed.

react-native run-android

Please also see: Uncaught TypeError: Cannot read property 'forEach' of undefined, on a KitchenSink demo

Happy Coding :-)

Answer 4

Install the Expo modules

npm install --save

i.e.

npm install expo --save