Fix process.stdout exiting before done

In Node v6 process.nextTick exit causes long messages from stdout.write
to exit before the data is finished writing

Author: David Cheung

bin/lb-ng.js

@@ -5,6 +5,7 @@ var SG = require('strong-globalize');
 SG.SetRootDir(path.resolve(__dirname, '..'));
 var g = SG();
 var fs = require('fs');
+var Promise = require('bluebird');
 var semver = require('semver');
 var optimist = require('optimist');
 var generator = require('loopback-sdk-angular');
@@ -55,9 +56,13 @@ function runGenerator() {
   // used to have a bug where it prevented the application from exiting.
   // To work around that issue, we are explicitly exiting here.
   //
-  // The exit is deferred to the next tick in order to prevent the Node bug:
+  // The exit is deferred to both stdout and err is drained
+  // in order to prevent the Node bug:
   // https://github.com/joyent/node/issues/3584
-  process.nextTick(function() {
+  Promise.all([
+    waitForEvent(process.stdout, 'drain'),
+    waitForEvent(process.stderr, 'drain')
+  ]).then(function() {
     process.exit();
   });
 }
@@ -79,3 +84,10 @@ function assertLoopBackVersion() {
     process.exit(1);
   }
 }
+
+function waitForEvent(obj, name) {
+  return new Promise(function(resolve, reject) {
+    obj.once(name, resolve);
+    obj.once('error', reject);
+  });
+}

package.json

@@ -31,6 +31,7 @@
     "node": ">= 0.8.0"
   },
   "dependencies": {
+    "bluebird": "^1.2.4",
     "loopback-sdk-angular": "^1.1.1",
     "optimist": "^0.6.1",
     "semver": "^2.2.1",

test/fixtures/app.js

@@ -6,6 +6,13 @@
 var loopback = require('loopback');
 var app = loopback();
 
+// model creation is added so output has enough content to reproduce
+// issue where node v6 to chunk output of child_process and
+// nextTick exit before finish writing (see PR #45)
+app.dataSource('db', { connector: 'memory' });
+var User = loopback.createModel('User');
+app.model(User, { dataSource: 'db' });
+
 app.set('restApiRoot', '/rest-api-root');
 
 module.exports = app;

test/lb-ng.test.js

@@ -73,6 +73,13 @@ describe('lb-ng', function() {
     });
   });
 
+  it('does not truncate the output', function() {
+    return runLbNg(sampleAppJs)
+      .spread(function(script, stderr) {
+        expect(script).to.match(/\}\)\(window, window.angular\);/);
+      });
+  });
+
   //-- Helpers --
 
   function runLbNg() {