Hermes is an open-source JavaScript engine optimized for running React Native apps on Android. For many apps, simply enabling Hermes will result in improved start-up time, decreased memory usage, and smaller app size.
Questions tagged [react-native-hermes]
111 questions
22
votes
1 answer
duplicate symbol 'folly::exception_wrapper::from_exception_ptr(std::exception_ptr&&)' React Native 0.66 with hermes enabled
After updating my app to react-native v0.66.0, I keep getting this error if hermes is enabled. I tried to delete DerivedData folder, podfile podfile.lock... but nothing helped
terminal output
duplicate symbol…

cuongtd
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14
votes
6 answers
Getting "java.lang.UnsatisfiedLinkError: couldn't find DSO to load: libhermes.so" error
I'm in the process of migrating a React Native project from react-native version 0.58.5 to 0.60.4.
For the Android part I've done all the changes mentioned here
I let Hermes disabled in my app build.gradle file:
project.ext.react = [
entryFile:…

cjosepha
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13
votes
1 answer
React native 0.61.5 Crashlytics missing libhermes.so: SoLoader.java com.facebook.soloader.SoLoader.assertInitialized
I am building a React-Native application, everything worked fine until I decided to upgrade from version 0.59.x to v 0.61.5.
When I try to release my app in the play store, I've got a lot of crashes reported by Firebase Crashlytics (v 6.2.0) -- even…

Kruupös
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12
votes
6 answers
Library not loaded: @rpath/hermes.framework/hermes
I have enabled Hermes in my react-native(v0.64) Application. Everytime I run app I get following stack trace.
dyld: dyld cache load error: shared cache file open() failed
dyld: Library not loaded: @rpath/hermes.framework/hermes
Referenced from:…

Manish Mahajan
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12
votes
2 answers
React-Native: Hermes is not enabled
I am trying to enable Hermes in a new project but despite I have enabled it in android/app/build.gradle it is not enabled. I am not able to see Engine: Hermes text in app as described in documentation. I am using WebStorm 2019.2 project…

Olcay Ertaş
- 5,987
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11
votes
3 answers
Flipper: Flipper Hermes debugger does not show
Flipper Hermes debugger does not show
I would like to ask how to make him display normally?
react-native:0.62.2 (Update from 0.61 to 0.62.2)
https://fbflipper.com/
https://reactnative.dev/docs/hermes
error message:
Metro is connected but no Hermes…

ebyte
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11
votes
1 answer
React-native 0.61.2 with hermes disassembling index.android.bundle
I created a release build of my app with react-native 0.61.2 and enabled Hermes.
In my Crashlytics I receive information about crashes along with stacktraces. Perviously I used to apply apktool to extract index.android.bundle from my apk, and it…

Ksenia
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9
votes
5 answers
Installing hermes-engine (0.71.2) got stuck react native
I have created a new react native project and then install npm , run command bundle install and then then cd iOS pod install but it got stuck on
Installing React-perflogger (0.71.2)
Installing React-runtimeexecutor (0.71.2)
Installing ReactCommon…

Engr.Aftab Ufaq
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9
votes
0 answers
How can I enable Hermes engine in an updated react-native project?
I'm working on a react-native project that was originally using an old react-native version. Updating the project to use the latest react-native version, has been quite succesful in other ways. However, I have not been able to enable Hermes engine…

Mehrad
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7
votes
1 answer
How can I enable the Hermes engine in react-native
I followed the official docs to enable the Hermes engine in my app but the following always returns false:
const isHermes = () => !!global.HermesInternal;
console.log('>>>>>>>>>>>>>', isHermes());
The changes I made are setting the…

kimobrian254
- 557
- 3
- 10
7
votes
0 answers
React Native 0.60.4 / couldn't find DSO to load: libhermes.so on Firebase Test Lab
I have got this error at startup ONLY when testing my react native app on Firebase Test Lab (Robo)
java.lang.UnsatisfiedLinkError: couldn't find DSO to load: libhermes.so
Tested on several devices with different API, it works only on API 21 and 22.…

Gilles
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6
votes
1 answer
TypeError: undefined is not a function, js engine: hermes
My React Native (0.66.3) app today pops up an error with a stable code which hasn't had any change for quite some time. It is on macOS Big Sur. Here is the error:
ERROR TypeError: undefined is not a function, js engine: hermes
Error: ENOENT: no…

user938363
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6
votes
0 answers
React Native Android app release build (using Hermes) is only slow when downloaded through the Play Store
We have a React Native Android app with Hermes enabled. We are seeing a huge performance issue with our app when it is downloaded through the Play Store (7s+ boot time). The same build runs very fast when installed directly in APK format (<2s boot…

feiyingx
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5
votes
1 answer
Expo Cannot read property 'getConstants' of null, js engine: hermes
When running an Expo app, you may encounter the error message 'Cannot read property 'getConstants' of null, js engine: hermes'.
I don't know the reason and I don't know where to fix it.
️Error Image:
I upgraded the SDK from 46 to 48 (used the…

최선아
- 51
- 3
5
votes
0 answers
"Error: ENOENT: no such file or directory", when using React Native with Hermes
Whenever there is an error in my code while running expo with Hermes locally, I get this error message as well:
Error: ENOENT: no such file or directory, open…

FiveDollarMilkshake
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- 3