build - minify via gulp-uglify-es instead of uglifyify

gulpfile.js

@@ -484,16 +484,6 @@ function generateBundler(opts, performBundle) {
     NODE_ENV: opts.devMode ? 'development' : 'production',
   }))
 
-  // Minification
-  if (opts.minifyBuild) {
-    bundler.transform('uglifyify', {
-      global: true,
-      mangle: {
-        reserved: [ 'MetamaskInpageProvider' ]
-      },
-    })
-  }
-
   if (opts.watch) {
     bundler = watchify(bundler)
     // on any file update, re-runs the bundler
@@ -567,6 +557,16 @@ function bundleTask(opts) {
         .pipe(sourcemaps.init({ loadMaps: true }))
     }
 
+    // Minification
+    if (opts.minifyBuild) {
+      buildStream = buildStream
+      .pipe(uglify({
+        mangle: {
+          reserved: [ 'MetamaskInpageProvider' ]
+        },
+      }))
+    }
+
     // Finalize Source Maps (writes .map file)
     if (opts.buildSourceMaps) {
       buildStream = buildStream

package.json

@@ -272,7 +272,6 @@
     "stylelint-config-standard": "^18.2.0",
     "tape": "^4.5.1",
     "testem": "^2.0.0",
-    "uglifyify": "github:MetaMask/uglifyify#keep-flags",
     "vinyl-buffer": "^1.0.1",
     "vinyl-source-stream": "^2.0.0",
     "watchify": "^3.9.0"