target nodejs v8 (BREAKING)

This adds support for async/await. Prior to this patch, transpiled code
using these features had references to "regeneratorRuntime", which gives
errors at runtime when used in Fuse apps since "regeneratorRuntime" is
not defined there.

Node.js v8 uses V8 v5.8, which is older than the version(s) we're
currently using in Fuse apps, so it's fairly safe to assume that all
JavaScript features used by transpiled code are supported in Fuse.

Author: mortend

src/server.js

@@ -5,7 +5,7 @@ var babel_plugin_proposal_decorators = require("@babel/plugin-proposal-decorator
 var babel_plugin_proposal_class_properties = require("@babel/plugin-proposal-class-properties");
 var babel_plugin_proposal_object_rest_spread = require("@babel/plugin-proposal-object-rest-spread");
 var babel_plugin_proposal_optional_chaining = require("@babel/plugin-proposal-optional-chaining");
-var babel_plugin_transform_typescript_metadata = require('babel-plugin-transform-typescript-metadata');
+var babel_plugin_transform_typescript_metadata = require("babel-plugin-transform-typescript-metadata");
 var http = require("http");
 
 function transpile(filename, code) {
@@ -24,13 +24,21 @@ function transpile(filename, code) {
         babel_plugin_proposal_object_rest_spread,
         babel_plugin_proposal_optional_chaining
     ];
+    var target = [
+        babel_preset_env,
+        {
+            "targets": {
+                "node": "8"
+            }
+        }
+    ];
 
     if (ext == "ts") {
         return babel.transform(code, {
             filename: filename,
             presets: [
                 babel_preset_typescript,
-                babel_preset_env
+                target
             ],
             plugins: plugins,
             sourceMaps: "inline"
@@ -39,7 +47,7 @@ function transpile(filename, code) {
         return babel.transform(code, {
             filename: filename,
             presets: [
-                babel_preset_env
+                target
             ],
             plugins: plugins,
             sourceMaps: "inline"