bundling refactor

common/buildPluginExternals.js

@@ -0,0 +1,19 @@
+const useBundleExternals = require('./useBundleExternals');
+const getBundleExternals = require('./getBundleExternals');
+
+function buildExternalsFromDependencies(packageJson) {
+  if (useBundleExternals == 'true') {
+    return getBundleExternals();
+  }
+  const { dependencies, optionalDependencies } = packageJson;
+  const externals = {};
+  for (let dep in dependencies || {}) {
+    externals[dep] = `commonjs ${dep}`;
+  }
+  for (let dep in optionalDependencies || {}) {
+    externals[dep] = `commonjs ${dep}`;
+  }
+  return externals;
+}
+
+module.exports = buildExternalsFromDependencies;