OPS: Add Hermes

android/app/build.gradle

@@ -76,7 +76,8 @@ import com.android.build.OutputFile
  */
 
 project.ext.react = [
-    entryFile: "index.js"
+    entryFile: "index.js",
+    enableHermes: true,  // clean and rebuild if changing
 ]
 
 apply from: "../../node_modules/react-native/react.gradle"
@@ -98,13 +99,26 @@ def enableSeparateBuildPerCPUArchitecture = false
 def enableProguardInReleaseBuilds = false
 
 /**
- * Use international variant JavaScriptCore
- * International variant includes ICU i18n library and necessary data allowing to use
- * e.g. Date.toLocaleString and String.localeCompare that give correct results
- * when using with locales other than en-US.
- * Note that this variant is about 6MiB larger per architecture than default.
+ * The preferred build flavor of JavaScriptCore.
+ *
+ * For example, to use the international variant, you can use:
+ * `def jscFlavor = 'org.webkit:android-jsc-intl:+'`
+ *
+ * The international variant includes ICU i18n library and necessary data
+ * allowing to use e.g. `Date.toLocaleString` and `String.localeCompare` that
+ * give correct results when using with locales other than en-US.  Note that
+ * this variant is about 6MiB larger per architecture than default.
+ */
+def jscFlavor = 'org.webkit:android-jsc:+'
+
+/**
+ * Whether to enable the Hermes VM.
+ *
+ * This should be set on project.ext.react and mirrored here.  If it is not set
+ * on project.ext.react, JavaScript will not be compiled to Hermes Bytecode
+ * and the benefits of using Hermes will therefore be sharply reduced.
  */
-def useIntlJsc = false
+def enableHermes = project.ext.react.get("enableHermes", true);
 
 android {
     compileSdkVersion rootProject.ext.compileSdkVersion
@@ -131,8 +145,11 @@ android {
             include "armeabi-v7a", "x86", "arm64-v8a", "x86_64"
         }
     }
+  
     buildTypes {
         release {
+            // Caution! In production, you need to generate your own keystore file.
+            // see https://facebook.github.io/react-native/docs/signed-apk-android.
             minifyEnabled enableProguardInReleaseBuilds
             proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
         }
@@ -148,18 +165,30 @@ android {
                 output.versionCodeOverride =
                         versionCodes.get(abi) * 1048576 + defaultConfig.versionCode
             }
+
         }
     }
+
+    packagingOptions {
+        pickFirst '**/armeabi-v7a/libc++_shared.so'
+        pickFirst '**/x86/libc++_shared.so'
+        pickFirst '**/arm64-v8a/libc++_shared.so'
+        pickFirst '**/x86_64/libc++_shared.so'
+        pickFirst '**/x86/libjsc.so'
+        pickFirst '**/armeabi-v7a/libjsc.so'
+    }
 }
 
 dependencies {
     implementation fileTree(dir: "libs", include: ["*.jar"])
     implementation "com.facebook.react:react-native:+"  // From node_modules
-    // JSC from node_modules
-    if (useIntlJsc) {
-        implementation 'org.webkit:android-jsc-intl:+'
+
+    if (enableHermes) {
+      def hermesPath = "../../node_modules/hermesvm/android/";
+      debugImplementation files(hermesPath + "hermes-debug.aar")
+      releaseImplementation files(hermesPath + "hermes-release.aar")
     } else {
-        implementation 'org.webkit:android-jsc:+'
+      implementation jscFlavor
     }
 }
 

android/app/src/main/java/io/bluewallet/bluewallet/MainApplication.java

@@ -1,13 +1,14 @@
 package io.bluewallet.bluewallet;
 
 import android.app.Application;
-
+import android.util.Log;
 import com.facebook.react.PackageList;
+import com.facebook.hermes.reactexecutor.HermesExecutorFactory;
+import com.facebook.react.bridge.JavaScriptExecutorFactory;
 import com.facebook.react.ReactApplication;
 import com.facebook.react.ReactNativeHost;
 import com.facebook.react.ReactPackage;
 import com.facebook.soloader.SoLoader;
-
 import java.util.List;
 
 public class MainApplication extends Application implements ReactApplication {