# react-native-v8-1

**Repository Path**: mirrors_keybase/react-native-v8-1

## Basic Information

- **Project Name**: react-native-v8-1
- **Description**: Opt-in V8 runtime for React Native Android
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-25
- **Last Updated**: 2026-02-15

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

[![npm version](https://badge.fury.io/js/react-native-v8.svg)](https://badge.fury.io/js/react-native-v8)
[![CircleCI](https://circleci.com/gh/Kudo/react-native-v8.svg?style=svg)](https://circleci.com/gh/Kudo/react-native-v8)

# React Native with V8 Runtime

The aim of this project is to support V8 runtime for React Native. Designed as opt-in package, it should easy to integrate with existing React Native projects.

## Integration with React Native

To make RN integration easier, we publish prebuilt AAR into [npm](https://www.npmjs.com/package/react-native-v8).

The versioning is aligned with React Native but suffixed with a `-patch.N` in version
E.g.
If your React Native version is `0.60.0`, you should use react-native-v8 `>=0.60.0-patch.0 <0.60.1`.

Following steps will take 0.60.0 as example.

1. Install react-native-v8

```sh
yarn add 'react-native-v8@>=0.60.0-patch.0 <0.60.1'

# [OPTIONAL] If to use different V8 version
# yarn add 'v8-android@7.8.1'
```

2. Modify your React Native build.gradle

```diff
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -161,11 +161,18 @@ android {
             }
         }
     }
+
+    packagingOptions {
+        // Make sure libjsc.so does not packed in APK
+        exclude "**/libjsc.so"
+    }
 }

 dependencies {
     implementation fileTree(dir: "libs", include: ["*.jar"])
     implementation "com.facebook.react:react-native:+"  // From node_modules
+    // Add v8-android - prebuilt libv8android.so into APK 
+    implementation 'org.chromium:v8-android:+'

     // JSC from node_modules
     if (useIntlJsc) {
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -24,8 +24,12 @@ allprojects {
     repositories {
         mavenLocal()
         maven {
-            // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
-            url("$rootDir/../node_modules/react-native/android")
+            // Replace AAR from original RN with AAR from react-native-v8
+            url("$rootDir/../node_modules/react-native-v8/dist")
+        }
+        maven {
+            // prebuilt libv8android.so
+            url("$rootDir/../node_modules/v8-android/dist")
         }
         maven {
             // Android JSC is installed from npm
```

3. Gradle rebuild or `react-native run-android`

4. Start application and could verify by JS `global._v8runtime().version` which expected to return V8 version.

## Builtin JavaScript object

`global._v8runtime()` has some builtin information such as v8 version.

```js
console.log(`V8 version is ${global._v8runtime().version}`);
```

Please note that `global._v8runtime()` existed only for V8 enabled environment but not React Native remote debugging mode.
For remote debugging mode, the JavaScript actually runs on Chrome from your host and there is no V8Runtime. 
   
## V8 Features Flags
V8 provides many feature flags and the most important one should be JIT.
Currently JIT is disabled for [V8 lite mode](https://v8.dev/blog/v8-lite)

react-native-v8 use the V8 shared libray from [v8-android-buildscripts](https://github.com/Kudo/v8-android-buildscripts).
For detailed V8 features, please check [there](https://github.com/Kudo/v8-android-buildscripts/blob/master/README.md#v8-feature-flags).

## FAQ

### How to reduce APK size ?

The V8 currently bundled by default supports [Intl](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl) and the ICU data costs about 7MiB per ABI.
If you are not going to use `Intl`, you could use no-Intl version to reduce APK size.
(jsc-android and Hermes have no Intl by default)

1. Add `v8-android-nointl` package
```sh
$ yarn add v8-android-nointl
```

2. Modify gradle dependency to use `v8-android-nointl`
```diff
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -29,7 +29,7 @@ allprojects {
         }
         maven {
             // prebuilt libv8android.so
-            url("$rootDir/../node_modules/v8-android/dist")
+            url("$rootDir/../node_modules/v8-android-nointl/dist")
         }
         maven {
             // Android JSC is installed from npm
```

## TODO

- [x] Performance comparison with JavaScriptCore in React Native

  Please check https://github.com/Kudo/react-native-js-benchmark for the benchmark and result
      
- [ ] V8 inspector integration
- [ ] V8 snapshot integration
- [ ] V8 code cache experiment