This package is part of the React Native CLI. It contains commands for managing the Hermes engine.
Installation
yarn add @react-native-community/cli-hermes
Commands
profile-hermes
Usage:
react-native profile-hermes [destinationDir] <flag>
Pull and convert a Hermes tracing profile to Chrome tracing profile, then store it in the directory of the local machine.
destinationDir
is optional, if provided, pull the file to that directory
default: pull to the current React Native app root directory
Options
--filename <string>
File name of the profile to be downloaded, eg. sampling-profiler-trace8593107139682635366.cpuprofile.
default: pull the latest file
--raw
Pulls the original Hermes tracing profile without any transformation
--sourcemap-path <string>
The local path to your source map file if you generated it manually, ex. /tmp/sourcemap.json
--generate-sourcemap
Generate the JS bundle and source map in os.tmpdir()
--port <number>
The running metro server port number
default: 8081
--appId <string>
Specify an applicationId
to launch after build. If not specified, package
from AndroidManifest.xml will be used.
--appIdSuffix <string>
Specify an applicationIdSuffix
to launch after build.
--host <string>
The host of the packager.
default: localhost
Notes on source map
This step is recommended in order for the source map to be generated:
If you are planning on building a debug APK, that will run without the packager, by invoking ./gradlew assembleDebug
you can simply set bundleInDebug: true
in your app/build.gradle file, inside the project.ext.react
map.