fix issue in which some files were not triggered change event

lib/pipeline/watch.js

@@ -1,4 +1,5 @@
 let chokidar = require('chokidar');
+let path = require('path');
 
 let fs = require('../core/fs.js');
 
@@ -37,7 +38,16 @@ class Watch {
     let filesToWatch = [];
 
     for (let targetFile in appConfig) {
-      filesToWatch.push(appConfig[targetFile]);
+      let files = appConfig[targetFile];
+      let fileGlob = files;
+
+      // workaround for imports issue
+      // so embark reacts to changes made in imported js files
+      if ((!Array.isArray(files) || files.length === 1)) {
+        fileGlob = path.join(path.dirname(files[0]), '**', '*.*');
+      }
+
+      filesToWatch.push(fileGlob);
     }
 
     this.watchFiles(