amplify-js: Unable to use signIn - Cannot read property 'computeModPow' of undefined

For RN 0.60.4 for iOS using Cocoa Pods with a Podfile containing:

...
require_relative '../node_modules/@react-native-community/cli-platform-ios/native_modules'
...
use_native_modules!
...

if amazon-cognito-identity-id is not installed as a direct dependency of the npm project, it is not included in dependencies in the output of react-native-config which is the basis for inclusion via use_native_modules.

Just running react-native link amazon-cognito-identity-js results in:

error Unknown dependency. Make sure that the package you are trying to link is already installed in your "node_modules" and present in your "package.json" dependencies. Run CLI with --verbose flag for more details.

The following:

• Running

npm add amazon-cognito-identity-js
cd ios; pod install; cd ..

• Cleaning & Building

resolved the issue for me.

Okay so that was the problem: even though RN says it linked amazon-cognito-identity-js correctly, it did not link iOS correctly. To fix I did the following:

1. opened the XCode project and dragged node_modules/amazon-cognito-identity-js/ios/RNAWSCognito.xcodeproj to the Libraries folder in the XCode project.
2. Then I opened up Build Phases and dragged libRNAWSCognito.a to the Link Binary with Libraries section. This is found in XCode when you expand Libraries > RNAWSCognito.xcodeproj > Products.
3. Recompiled the project and it works!

My next question would be: is this a React Native problem or potentially a problem with the amazon-cognito-identity-js library? I don’t personally know much about how linking is done. I haven’t had many issues with other libraries in this regard.

@BenjaminWatts after you link using react-native link amazon-cognito-identity-js try uninstalling your app in android and react-native run-android again.

For anybody running into this error using both, react-native-navigation and aws-amplify, you need to manually link the RNAWSCognitoPackage() in the MainApplication.java file:

protected List<ReactPackage> getPackages() {
      // Add additional packages you require here
      // No need to add RnnPackage and MainReactPackage
      return Arrays.<ReactPackage>asList(
          // eg. new VectorIconsPackage()
        new RNAWSCognitoPackage()

      );
  }

I spent countless hours fixing this, so I hope it helps someone.

Thanks @MikaelStenstrand . You saved my day.

@brickmaker17 I think you are using cocoa pods.

$ react-native link amazon-cognito-identity-js
$ cd ios
$ pod update && pod install

It works for me.

Both amazon-cognito-identity-js and aws-amplify packages need to be installed?

@grifotv No, @aws-amplify/auth has amazon-cognito-identity-js as a dependency; you just need to run react-native link amazon-cognito-identity-js.

react-native link did not solve the problem, but running react-native link amazon-cognito-identity-js fixed it. Thx!

@jdeanwaite this is often caused by some react-native link issues. One of the things you need to check is that whether this module is correctly linked in to the android/ios native module. For example, you can check the MainApplication.java under android/app/src/.../ to see there is one RNAWSCognitoPackage() under MainReactPackage. Hope that could help you.

did you try react-native link amazon-cognito-identity-js instead of npm link amazon-cognito-identity-js?

It’s related to #194 , did u check this?

After a very frustrating afternoon following everyone’s suggestions, the only fix I found was to add the following lines to my app’s MainApplication.java. I don’t know why linking didn’t automatically generate these lines properly, but I’m excited to move on to other bugs 😃

import com.amazonaws.RNAWSCognitoPackage; … new RNAWSCognitoPackage()

The first line obviously goes along with other imports, and the second gets included within: protected List<ReactPackage> getPackages() { return Arrays.<ReactPackage>asList( HERE ) }

@MikaelStenstrand life saver!

Both amazon-cognito-identity-js and aws-amplify packages need to be installed?