Unable to load script from assets index.android.bundle on windows

Question

I'm trying to run my first React Native project for first time on my device (Android 4.2.2).

And I get:

unable to load script from assets index.android.bundle

Commands that I used:

1. cd (project directory)
2. react-native start
3. react-native run-android

Answer 1

I've encountered the same issue while following the React Native tutorial (developing on Linux and targeting Android).

This issue helped me resolve the problem in following steps.

1. (in project directory) mkdir android/app/src/main/assets
2. react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res
3. react-native run-android

You can automate the above steps by placing them in scripts part of package.json like this:

"android-linux": "react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res && react-native run-android"

Then you can just execute npm run android-linux from your command line every time.

Answer 2

If You are running your application on physical device and getting this error

unable to load script from assets index.android.bundle

try running the command:

adb reverse tcp:8081 tcp:8081

It workd for Me...

Answer 3

I spent hours trying to figure this issue out. My problem was not specific to Windows but is specific to Android.

Accessing the development server worked locally and in the emulator's browser. The only thing that did not work was accessing the development server in the app.

Starting with Android 9.0 (API level 28), cleartext support is disabled by default.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest ...>
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        ...
        android:usesCleartextTraffic="true"
        ...>
        ...
    </application>
</manifest>

See for more info: https://stackoverflow.com/a/50834600/1713216

Answer 4

Using npm version 4.3.0 react-native-cli version 2.01 react-native version 0.49.5

In the project directory,

• mkdir android/app/src/main/assets
• react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res
• react-native run-android

The file name has changed from index.android.js to index.js

Answer 5

I have faced the same problem with a real android device.

Solution: Based on this answer by Niltoid

1. Find your local IP
2. Open app and shake your Android device
3. Go Dev Setting and>Debug Server...
4. Paste your IP and port; X.X.X.X:8088" (where X's are your local IP)

for Mac user: open your network preference, here you will get your local IP.

Answer 6

If you are using Windows run the commands in the following way, or if you get an error "Cannot find entry file index.android.js"

1. mkdir android\app\src\main\assets

2. react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

3. react-native run-android

Answer 7

Had the same issue in mac, After spending 2 days i was finally able to get is working.

Since Emulator cellular data was turned off, I was getting the unable to load script from assets index.android.bundle make sure your bundle is running.

Make sure your Emulator cellular data is turned on by doing this package server was able to bundle index.android.js. Hope it helps for someone who is in development phase.

Answer 8

I've had this same issue for a number of months now. I initially used @Jerry's solution however, this was a false resolution as it didn't fully fix the problem. Instead, what it did was take every build as a production build meaning that any slight change you made in the app would mean that rebuilding the entire app is necessary.

While this is a temporal solution, it works horribly in the long term as you are no longer able to avail of React Native's amazing development tools such as hot reloading etc.

A proper solution is a shown:

In your MainApplication.java file, replace the following:

@Override
public boolean getUseDeveloperSupport() {
    return BuildConfig.DEBUG;
}

with

@Override
public boolean getUseDeveloperSupport() {
    return true;
}

as for some reason BuildConfig.DEBUG always returned false and resulted in a bundle file in the assets directory.

By manually setting this to true, you're forcing the app to use the packager. This WON't work in production so be sure to change it to false or the default value.

Don't forget also to run

$ adb reverse tcp:8081 tcp:8081

Answer 9

You can follow the instruction mentioned on the official page to fix this issue. This issue occur on real device because the JS bundle is located on your development system and the app inside your real device is not aware of it's location.

Answer 10

1 Go to your project directory and check if this folder exists android/app/src/main/assets

1. If it exists then delete two files viz index.android.bundle and index.android.bundle.meta
2. If the folder assets don't exist then create the assets directory there.

2.From your root project directory do

cd android && ./gradlew clean

3.Finally, navigate back to the root directory and check if there is one single entry file calledindex.js

• If there is only one file i.e. index.js then run following command react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

• If there are two files i.e index.android.js and index.ios.js then run this react-native bundle --platform android --dev false --entry-file index.android.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

  4. Now run react-native run-android

Answer 11

In my case, I have removed below line from MainApplication.java. (Which is previously mistakenly added by me.):-

import com.facebook.react.BuildConfig;

After that Clean Project and hit command

react-native run-android

Answer 12

OS: Windows

Another way to resolve this problem after trying two methods above
(because I installed SDK not in DEFAULT LOCATION like C:\users\"user_name"\appdata\local\sdk)

If you noticed that command line announced: "'adb' is not recognized as an internal or external command..."

So this is how I get over:
Examples: I installed SDK in D:\Android\sdk
So I will insert path in System Variables 2 more lines:

D:\Android\sdk\tools  
D:\Android\sdk\platform-tools  

(If you don't know how to edit path System Variables, here's the topic: https://android.stackexchange.com/questions/38321/what-do-i-type-in-path-variable-for-adb-server-to-start-from-cmd/38324)

Then I run cmd again: react-native run-android

It worked for me.

Answer 13

I was also facing this problem because when I run projects on the emulator its working fine but on a real device it gives this error. So I resolve this problem by the following solution

1st step: First of all open cmd and go to your SDK manager Platform-tools folder

cd C:Development\Android\Sdk\Platform-tools

2nd step: now run this command :

adb devices

after this command check your device listed in command prompt

3rd step: now run this

adb reverse tcp:8081 tcp:8081

Now your setup is done

4th step: Go to your project directory and run this command

react-native run-android

Answer 14

For IOS:

In a terminal:

cd ios

Remove the build folder with: rm -r build

Run again: react-native run-ios

Alternatively, you could open Finder, navigate to YOUR_PROJECT/ios and delete the build folder.

Then run again: react-native run-ios

For ANDROID:

In a terminal:

cd android/app

Remove the build folder with: rm -r build

Run again: react-native run-android

Alternatively, you could open Finder, navigate to YOUR_PROJECT/android/app and delete the build folder.

Then run again: react-native run-android

Answer 15

For this problem I just solve it by running:

react-native start

then

adb reverse tcp:8081 tcp:8081

on command line. And then i can run:

react-native run-android

So i will not waste my time to run:

react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

every time.

Answer 16

I had issue with McAfee on my mac blocking port 8081, had to change it to 8082.

First run your package server:

react-native start --port 8082

Open another terminal, start the android app as usual:

react-native run-android

Once it finishes, now rewrite the tcp port that adb tunnels:

adb reverse tcp:8081 tcp:8082

See the list of adb tcp tunnels:

adb reverse --list

You should now see a heartwarming message:

(reverse) tcp:8081 tcp:8082

Go to your app and reload, done!

PS: Don't change anything in the app Dev settings, if you added "localhost:8082", just remove it, leave it blank.

EDIT: To all the McAfee victims out there, there's easier solution if you have root access, just temporarily kill the McAfee process sitting on port 8081 and no need for port change at all:

sudo launchctl remove com.mcafee.agent.macmn

Answer 17

Ubuntu

first time, I created new app with react-native init project-name. I got the same error. so i do the following steps to resolve this in my case.

1. Firstly run sudo chown user-name-of-pc /dev/kvm in my case.

2. While debugging from your Android phone, select Use USB to Transfer photos (PTP).

3. Create Folder assets in project-name/android/app/src/main

4. make sure index.js be avaiable into your project root directory and then run below command from console after cd project-name directory.

react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

or for index.android.js then

react-native bundle --platform android --dev false --entry-file index.android.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

5. run command ./studio.sh in android-studio/bin directory. It will opens up Android Studio.

6. run command react-native run-android.

Answer 18

Make sure metro builder is running to make your physical device and server sync

First, run this command to run metro builder

npm start

Then you can start the build in react native

react-native run-android

Their should be no error this time. If you want your code to be live reload on change. Shake your device and then tap Enable Live Reload

Answer 19

Make sure that you have added /path/to/sdk/platform-tools to your path variable.

When you run react-native run-android, it runs adb reverse tcp:< device-port > tcp:< local-port > command to forward the request from your device to the server running locally on your computer. You will see something like this if adb is not found.

/bin/sh: 1: adb: not found
Starting the app (.../platform-tools/adb shell am start -n 
com.first_app/com.first_app.MainActivity...
Starting: Intent { cmp=com.first_app/.MainActivity }

Answer 20

It may be caused by unlinked assets in your React Native project code base, like when you renames your project application/bundle id or adds an external package without link it properly, for example.

Simply try it in your project root directory:

react-native link

react-native run-android

Answer 21

This problem also happens if you define an android:networkSecurityConfig in your main AndroidManifest.xml. The android:usesCleartextTraffic="true" in your debug AndroidManifest.xml will be ignored.

To fix this issue, you have to configure the app to allow http traffic to localhost.

Create a file android/src/debug/res/xml/network_security_config.xml:

<?xml version="1.0" encoding="utf-8" ?>
<network-security-config>
    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">localhost</domain>
    </domain-config>
</network-security-config>

And reference it in android/src/debug/AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8" ?>
<manifest 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools">

    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

    <application 
        android:networkSecurityConfig="@xml/network_security_config" 
        tools:targetApi="28" 
        tools:ignore="GoogleAppIndexingWarning" />
</manifest>

Further infos here: https://medium.com/astrocoders/i-upgraded-to-android-p-and-my-react-native-wont-connect-to-my-computer-to-download-index-delta-42580377e1d3

Answer 22

using npx before the command did work for me, and the command becomes like following.

npx react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

why we use npx, here is the post Difference between npx and npm?

Answer 23

If when running react-native run-android command the second line of the trace is

JS server not recognized, continuing with build...

it means packager for the app cannot be started and the app will fail to load without some extra steps. Note that the end of the trace still reports success:

BUILD SUCCESSFUL

The problem is probably some port conflict (in my case it was the default IIS site that I completely forgot about). Another manifestation of the problem would be a failure to open http://localhost:8081/debugger-ui URL in Chrome.

Once the port conflict is resolved the trace will report

Starting JS server...

then an additional Node window will open (node ...cli.js start) and the app will load/reload successfully.

After that you should be able to open debug console in Chrome with http://localhost:8081/debugger-ui.

Answer 24

I had the same issue even when running on a simulator. I did a quick workaround so that I could have the normal dev workflow.

private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
  @Override
  public boolean getUseDeveloperSupport() {
    // return true here to load JS from the packager
    // BuildConfig.DEBUG for me was set to false which meant it
    // it was always trying to load the assets from assets folder.
    return true;
  }

  @Override
  protected String getJSMainModuleName() {
    return "index";
  }
};

Probably will have to revert the change when trying to do a production build.

Answer 25

I think you don't have yarn installed try installing it with chocolatey or something. It should be installed before creating your project (react-native init command).

No need of creating assets directory.

Reply if it doesn't work.

Edit: In the recent version of react-native they have fixed it. If you want complete freedom from this just uninstall node (For complete uninstallation Completely remove node refer this link) and reinstall node, react-native-cli then create your new project.

Answer 26

don't forget turn on internet in emulator device, I resovled this error, it work perfect :V I get this error because i turn off internet to test NetInfo :D

Answer 27

This is a general error message, you may have encountered during the react native application development. So In this tutorial we are going to provide solution to this issue.

Issue Description : Unable to load script from assets index.android.bundle on windows Unable to load script from assets index.android.bundle on windows

Follow the below steps to solve above issue :

Step-1 : Create "assets" folder inside your project directory Now create assets folder inside the project directory that is "MobileApp\android\app\src\main". You can manually create assets folder :

< OR >

you can create folder by using command as well. Command : mkdir android/app/src/main/assets

Step-2 : Running your React Native application Lets run the below command to run the react native application in emulator or physical device.

Switch to project directory. cd MobileApp

Run the below command that helps to bundle you android application project.

react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

Run the Final step to run react native application in emulator or physical device. react-native run-android

< OR >

Also you can combine last two command in one, In this case case you have to execute command only once.

react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res && react-native run-android

< OR >

You can automate the above steps by placing them in scripts part of package.json like this:

"android-android": "react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res && react-native run-android"

If everything is set up correctly, you should see your new app running in your Android emulator shortly.

Answer 28

I have just encounterred exactly the same problem and solved it. So hope to be helpful.

Suppose you are assemblling a release application package (.apk)

1. Check if your assets folder exist?: \android\app\src\main\assets If not, create one.

2. After executing "Assemble Release", check if there is anything in that folder(\android\app\src\main\assets) If not, find js bundle file(index.android.bundle), which should be in more than one of the following paths:

   *a)\android\app\build\intermediates\merged_assets\release\out\index.android.bundle

   b)\android\app\build\intermediates\merged_assets\release\mergeReleaseAssets\out\index.android.bundle

   c)\android\app\build\intermediates\assets\release\index.android.bundle

   d)\android\app\build\generated\assets\react\release\index.android.bundle*

A better way is to use "Everything" to search the file name: index.android.bundle.

3. Then copy this file into your assets folder(\android\app\src\main\assets\index.android.bundle)

4. Go back to powershell or command console, execute:

react-native run-android --variant=release

It should work.

Good luck!

Answer 29

first of all check your assets folder exist in this location \android\app\src\main\assets

if no then run this command in terminal

react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

then run your project on your android device using

react-native run-android

Answer 30

Actually, in my situation (React-native version 0.61.5 and trying to install debug APK on device) none of the answers helped me, my solution was adding bundleInDebug: true to android/app/build.gradle like this:

project.ext.react = [
    entryFile: "index.js",
    enableHermes: true,  // clean and rebuild if changing
    bundleInDebug: true
]