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.

The versioning is aligned with React Native with a suffix -patch.N in version. E.g., if your React Native version is 0.65.1, you should use react-native-v8 >=0.65.1-patch.0 <0.65.1.

Following steps will take 0.65.1 as an example.

1. Install react-native-v8

yarn add 'react-native-v8@>=0.65.1-patch.0 <0.65.2'

2. Modify your React Native build.gradle

--- 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:9.93.+'

     // 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-jit/dist")
         }
         maven {
             // Android JSC is installed from npm

Since V8 shared library is not ABI safe, the implementation 'org.chromium:v8-android:9.93.+' change above requires to pair with react-native-v8 release version. Please reference the mappings for the actual gradle dependency you need.

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.

react-native-v8 and v8-android-* mappings

| react-native-v8 version | v8-android* version | gradle dependency | Chromium V8 version | | ------------------------- | --------------------- | ------------------------------------------------- | ------------------- | | -- 0.67 | | | | | 0.67.3-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.67.2-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.67.1-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.67.0-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | -- 0.66 | | | | | 0.66.4-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.66.3-patch.1 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.66.2-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.66.1-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.66.0-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | -- 0.65 | | | | | 0.65.2-patch.1 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.65.2-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.65.1-patch.1 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | 0.65.1-patch.0 | 9.93.0 | implementation 'org.chromium:v8-android:9.93.+' | 9.3.345.16 | | -- 0.64 | | | | | 0.64.2-patch.1 | 9.88.0 | implementation 'org.chromium:v8-android:9.88.+' | 8.8.278.15 | | 0.64.2-patch.0 | 9.88.0 | implementation 'org.chromium:v8-android:9.88.+' | 8.8.278.15 | | 0.64.1-patch.0 | 9.88.0 | implementation 'org.chromium:v8-android:9.88.+' | 8.8.278.15 | | 0.64.0-patch.0 | 9.88.0 | implementation 'org.chromium:v8-android:9.88.+' | 8.8.278.15 | | -- 0.63 | | | | | 0.63.4-patch.1 | 9.88.0 | implementation 'org.chromium:v8-android:9.88.+' | 8.8.278.15 | | 0.63.4-patch.0 | 8.84.0 | implementation 'org.chromium:v8-android:8.84.+' | 8.4.371.19 | | 0.63.3-patch.0 | 8.84.0 | implementation 'org.chromium:v8-android:8.84.+' | 8.4.371.19 | | 0.63.2-patch.1 | 8.84.0 | implementation 'org.chromium:v8-android:8.84.+' | 8.4.371.19 | | 0.63.1-patch.0 | 8.84.0 | implementation 'org.chromium:v8-android:8.84.+' | 8.4.371.19 | | 0.63.0-patch.0 | 8.80.1 | implementation 'org.chromium:v8-android:8.80.+' | 8.0.426.16 | | -- 0.62 | | | | | 0.62.2-patch.2 | 8.84.0 | implementation 'org.chromium:v8-android:8.84.+' | 8.4.371.19 | | 0.62.2-patch.1 | 8.80.1 | implementation 'org.chromium:v8-android:8.80.+' | 8.0.426.16 | | 0.62.1-patch.0 | 8.80.1 | implementation 'org.chromium:v8-android:8.80.+' | 8.0.426.16 | | 0.62.0-patch.0 | 8.80.1 | implementation 'org.chromium:v8-android:8.80.+' | 8.0.426.16 | | -- 0.59 | | | | | 0.59.10-patch.6 | 8.80.0 | implementation 'org.chromium:v8-android:7.8.+' | 8.0.426.16 |

Builtin JavaScript object

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

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 Variants

react-native-v8 uses V8 shared libray from v8-android-buildscripts. For detailed V8 features, please check there.

v8-android-jit is the default V8 variant we include in react-native-v8. This is a full featured V8 with both JIT and Intl. We provide other V8 variants to fulfill your needs.

| Package name | JIT | Intl | maven path | | --------------------- | --- | ---- | ------------------------------------------------------------ | | v8-android-jit | Yes | Yes | url("$rootDir/../node_modules/v8-android-jit/dist") | | v8-android-jit-nointl | Yes | No | url("$rootDir/../node_modules/v8-android-jit-nointl/dist") | | v8-android | No | Yes | url("$rootDir/../node_modules/v8-android/dist") | | v8-android-nointl | No | No | url("$rootDir/../node_modules/v8-android-nointl/dist") |

For instance, if you want to reduce memory usage, the non JIT variant, aka V8 lite mode. The following are further steps:

1. Add v8-android

$ yarn add v8-android

2. Modify the gradle dependency to use v8-android or other variants

--- a/android/build.gradle
+++ b/android/build.gradle
@@ -29,7 +29,7 @@ allprojects {
         }
         maven {
             // prebuilt libv8android.so
-            url("$rootDir/../node_modules/v8-android-jit/dist")
+            url("$rootDir/../node_modules/v8-android/dist")
         }
         maven {
             // Android JSC is installed from npm

react-native-v8 version should be

iOS Support (Experimented)

We did have experimented iOS support. To adopt V8 for Xcodeproj gets a little complicated, so we have a pre-shaped template. Please check react-native-template-v8 for more information.

FAQ

How to reduce APK size ?

The V8 currently bundled by default supports 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 have no Intl by default)

TODO

• [x] Performance comparison with JavaScriptCore in React Native

  Please check https://github.com/Kudo/react-native-js-benchmark for the benchmark and result

• [x] V8 inspector integration

• [ ] V8 snapshot integration

• [ ] V8 code cache experiment