This just might work

gulpfile.js

@@ -1,24 +1,55 @@
-var gulp = require("gulp");
-sourcemaps = require("gulp-sourcemaps"),
-  babel = require("gulp-babel"),
+var gulp = require("gulp"),
+  source = require('vinyl-source-stream'),
+  buffer = require('vinyl-buffer'),
+  sourcemaps = require("gulp-sourcemaps"),
   concat = require("gulp-concat"),
-  connect = require('gulp-connect');
+  connect = require('gulp-connect'),
+  browserify = require('browserify'),
+  watchify = require('watchify'),
+  babel = require('babelify');
 
-gulp.task("default", ['build'], function () {
-});
+
+function compile(watch) {
+  var bundler = watchify(browserify()
+  .require('./src/index.js', {
+    entry: true,
+    expose: 'ionic-native'
+  })
+  .transform(babel, {presets: ['es2015']}));
+
+  function rebundle() {
+    bundler.bundle()
+      .on('error', function(err) { console.error(err); this.emit('end'); })
+      .pipe(source('ionic-native.js'))
+      .pipe(buffer())
+      .pipe(sourcemaps.init({ loadMaps: true }))
+      .pipe(sourcemaps.write('./'))
+      .pipe(gulp.dest('./dist'));
+  }
+
+  if (watch) {
+    bundler.on('update', function() {
+      console.log('-> bundling...');
+      rebundle();
+    });
+  }
+
+  rebundle();
+}
+
+function watch() {
+  return compile(true);
+}
+
+gulp.task("default", ['build'], function () { });
 
 gulp.task('build', function() {
-  return gulp.src("src/**/*.js")
-    .pipe(sourcemaps.init())
-    .pipe(babel())
-    .pipe(concat("ionic-native.js"))
-    .pipe(sourcemaps.write("."))
-    .pipe(gulp.dest("dist"));
+  return compile();
 });
 
-gulp.task('test', ['build', 'serve'], function() {
-
-})
+gulp.task('watch', function() {
+  return watch();
+});
 
 gulp.task('serve', function() {
   connect.server({