Hot reloading/Fast refreshing throws error: "_reactNativeMmkv.getString is not a function"

[a-eid]

I weirdly get this error somettimes / often

context:

I check for the token right away globally in the app, could it be that MMKV is not available then ?

[mrousavy]

MMKV is being initialized as soon as the bridge is being set (see here), afaik that is before JS code can be executed so it shouldn't be undefined. Could you try adding a breakpoint there to see what gets executed first?

[a-eid]

@mrousavy sorry, I'm not really sure how to do that, but will try and report back if I am successful.

[mrousavy]

Just open your project (.xcworkspace) in Xcode, press Command + Shift + O, search for "Mmkv" and open the Mmkv.mm file. then scroll to the line I linked, click the line number at the left and run the app from Xcode. it will pause execution at the breakpoint.

[a-eid]

@mrousavy it does hit the [MMKV initializeMMKV:nil]; line while on the native splash screen.

this log might be helpful.

[Tue Mar 09 2021 15:50:18.718]  LOG      Running "overlay/splash" with {"rootTag":31,"initialProps":{"componentId":"Component1"}}
[Tue Mar 09 2021 15:50:18.862]  WARN     Possible Unhandled Promise Rejection (id: 0):
TypeError: _reactNativeMmkv.MMKV.getString is not a function. (In '_reactNativeMmkv.MMKV.getString(TOKEN_KEY)', '_reactNativeMmkv.MMKV.getString' is undefined)
getToken@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:102145:43
_callee$@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:103078:41
tryCatch@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:1444:23
invoke@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:1617:32
tryCatch@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:1444:23
invoke@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:1517:30
http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:1527:21
tryCallOne@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:6438:16
http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:6539:27
_callTimer@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:30977:17
_callImmediatesPass@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:31016:17
callImmediates@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:31233:33
__callImmediates@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:5732:35
http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:5518:34
__guard@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:5715:15
flushedQueue@http://localhost:8081/index.bundle?platform=ios&dev=true&minify=false:5517:21
flushedQueue@[native code]
invokeCallbackAndReturnFlushedQueue@[native code]

I'm not sure why it says, Possible Unhandled Promise Rejection (id: 0):.

[a-eid]

please let me know if I can provide any more help.

[mrousavy]

So apparently all of this happens when Hot-Reloading, not normally when starting.

[crisfcodes]

I'm getting the similar error in expo app:

TypeError: _reactNativeMmkv.MMKV.getString is not a function. (In
 '_reactNativeMmkv.MMKV.getString(name)', '_reactNativeMmkv.MMKV.
getString' is undefined)

expo is supported?

[a-eid]

@Cristian05 this package does not work with expo.

[mrousavy]

Can you check if the newest version (1.1.6) works for you? Note that it requires some additional installation steps, see INSTALL.md.

Also, if you can't import the library see this issue which includes a temporary workaround. I'll find a fix that requires no native changes at all soon 👍

[a-eid]

when installing with reanimated 2, do we need to replace this ?

protected JSIModulePackage getJSIModulePackage() {
   return new ReanimatedJSIModulePackage();
}

[a-eid]

also the app failed building on android

> Task :app:compileDebugJavaWithJavac FAILED

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.7/userguide/command_line_interface.html#sec:command_line_warnings
290 actionable tasks: 271 executed, 19 up-to-date
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@react-native-community/async-storage/android/src/main/java/com/reactnativecommunity/asyncstorage/AsyncStorageModule.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: [2] Wrote GeneratedAppGlideModule with: [com.bumptech.glide.integration.okhttp3.OkHttpLibraryGlideModule, com.dylanvann.fastimage.FastImageOkHttpProgressGlideModule]
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/react-native-geolocation-service/android/src/main/java/com/agontuk/RNFusedLocation/LocationUtils.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@react-native-picker/picker/android/src/main/java/com/reactnativecommunity/picker/ReactPickerManager.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@sentry/react-native/android/src/main/java/io/sentry/react/RNSentryModule.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
/Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/main/java/com/alsagheer/AlsagheerJSIPackage.java:5: error: package com.reactnativemmkv does not exist
import com.reactnativemmkv.MmkvModule;
                          ^
/Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/main/java/com/alsagheer/MainApplication.java:44: error: cannot find symbol
            return new AlsagheerJSIPackage();
                       ^
  symbol: class AlsagheerJSIPackage
/Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/main/java/com/alsagheer/AlsagheerJSIPackage.java:16: error: cannot find symbol
        MmkvModule.install(jsContext, reactApplicationContext.getFilesDir().getAbsolutePath() + "/mmkv");
        ^
  symbol:   variable MmkvModule
  location: class AlsagheerJSIPackage
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/debug/java/com/alsagheer/ReactNativeFlipper.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
3 errors

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 16s

error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@react-native-community/async-storage/android/src/main/java/com/reactnativecommunity/asyncstorage/AsyncStorageModule.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: [2] Wrote GeneratedAppGlideModule with: [com.bumptech.glide.integration.okhttp3.OkHttpLibraryGlideModule, com.dylanvann.fastimage.FastImageOkHttpProgressGlideModule]
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/react-native-geolocation-service/android/src/main/java/com/agontuk/RNFusedLocation/LocationUtils.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@react-native-picker/picker/android/src/main/java/com/reactnativecommunity/picker/ReactPickerManager.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@sentry/react-native/android/src/main/java/io/sentry/react/RNSentryModule.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
/Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/main/java/com/alsagheer/AlsagheerJSIPackage.java:5: error: package com.reactnativemmkv does not exist
import com.reactnativemmkv.MmkvModule;
                          ^
/Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/main/java/com/alsagheer/MainApplication.java:44: error: cannot find symbol
            return new AlsagheerJSIPackage();
                       ^
  symbol: class AlsagheerJSIPackage
/Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/main/java/com/alsagheer/AlsagheerJSIPackage.java:16: error: cannot find symbol
        MmkvModule.install(jsContext, reactApplicationContext.getFilesDir().getAbsolutePath() + "/mmkv");
        ^
  symbol:   variable MmkvModule
  location: class AlsagheerJSIPackage
Note: /Users/ahmedeid/zeal/alsagheer-app-reactnative/android/app/src/debug/java/com/alsagheer/ReactNativeFlipper.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
3 errors

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 16s

    at makeError (/Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/execa/index.js:174:9)
    at /Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/execa/index.js:278:16
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at async runOnAllDevices (/Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/runOnAllDevices.js:94:5)
    at async Command.handleAction (/Users/ahmedeid/zeal/alsagheer-app-reactnative/node_modules/@react-native-community/cli/build/index.js:186:9)
info Run CLI with --verbose flag for more details.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[a-eid]

[mrousavy]

On which MMKV version are you? You need 1.1.6