added check for dataset_description.json presence

Author: suyashdb

validators/bids.js

@@ -149,6 +149,7 @@ BIDS = {
             participants = null,
             phenotypeParticipants = [],
             hasSubjectDir = false;
+        var hasDatasetDescription = false;
 
         var summary = {
             sessions: [],
@@ -213,6 +214,11 @@ BIDS = {
                 hasSubjectDir = true;
             }
 
+            // check for dataset_description.json presence
+            if (path === '/dataset_description.json') {
+                hasDatasetDescription = true;
+            }
+
             // ignore associated data
             if (utils.type.isAssociatedData(file.relativePath)) {
                 process.nextTick(cb);
@@ -404,6 +410,9 @@ BIDS = {
                 if (!hasSubjectDir) {
                     self.issues.push(new Issue({code: 45}));
                 }
+                if (!hasDatasetDescription) {
+                    self.issues.push(new Issue({code: 57}));
+                }
                 // check if participants file match found subjects
 
                 if (participants) {