Pre-publish changes before making a PR to RN CLI

[jessieAnhNguyen]

Summary:

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Implemented a new command to download Hermes Sampling Profiler to a local machine

1. Purpose:

• This new command helps users convert a Hermes tracing profile to Chrome tracing profile and pull it to the local machine
• Instructions on how to use Hermes: Using Hermes
• The hermes-profile-transformer tool that converts Hermes tracing profile to Chrome tracing profile Hermes-profile-transformer package

2. Usage:

react-native profile-hermes [destinationDir] <flag>

• 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

• --verbose

Lists commands and steps that are run internally to pull the file from Android device

• --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()

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.

Test Plan:

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• yarn
• yarn lint
• Test on a React Native app: use yarn link as instructed by the CLI's Testing Plan.
• Command react-native profile-hermes as per instruction above

Example output of running the command