Fix files not being watched

lib/core/engine.js

@@ -146,17 +146,11 @@ class Engine {
         self.currentAbi = abi;
         self.contractsJSON = contractsJSON;
         pipeline.build(abi, contractsJSON, null, function() {
+          self.watch.restart(); // Necessary because changing a file while it is writing can stop it from being watched
           self.events.emit('outputDone');
         });
       });
     });
-    // TODO: still need to redeploy contracts because the original contracts
-    // config is being corrupted
-    this.events.on('file-event', function(fileType, _path) {
-      if (fileType === 'asset') {
-        self.events.emit('asset-changed', self.contractsManager);
-      }
-    });
   }
 
   codeGeneratorService(_options) {
@@ -213,6 +207,11 @@ class Engine {
     });
 
     this.events.on('file-event', function (fileType) {
+      // TODO: still need to redeploy contracts because the original contracts
+      // config is being corrupted
+      if (fileType === 'asset') {
+        self.events.emit('asset-changed', self.contractsManager);
+      }
       // TODO: for now need to deploy on asset chanes as well
       // because the contractsManager config is corrupted after a deploy
       if (fileType === 'contract' || fileType === 'config') {
@@ -225,8 +224,8 @@ class Engine {
 
   fileWatchService(_options) {
     this.events.emit("status", "Watching for changes");
-    let watch = new Watch({logger: this.logger, events: this.events});
-    watch.start();
+    this.watch = new Watch({logger: this.logger, events: this.events});
+    this.watch.start();
   }
 
   webServerService() {

lib/pipeline/watch.js

@@ -9,6 +9,7 @@ class Watch {
   constructor(options) {
     this.logger = options.logger;
     this.events = options.events;
+    this.fileWatchers = [];
   }
 
   start() {
@@ -32,6 +33,19 @@ class Watch {
     this.logger.info("ready to watch file changes");
   }
 
+  restart() {
+    this.stop();
+    this.start();
+  }
+
+  stop() {
+    this.fileWatchers.forEach(fileWatcher => {
+      fileWatcher.close();
+      fileWatcher = null;
+    });
+    this.fileWatchers = [];
+  }
+
   watchAssets(embarkConfig, callback) {
     let self = this;
     let appConfig = embarkConfig.app;
@@ -102,6 +116,7 @@ class Watch {
     let configWatcher = chokidar.watch(files, {
       ignored: /[\/\\]\./, persistent: true, ignoreInitial: true, followSymlinks: true
     });
+    this.fileWatchers.push(configWatcher);
 
     configWatcher
       .on('add', path => changeCallback('add', path))