dynamically resolves comments path (#683)

Comments may be found in either ds:8 or ds:9 paths. This approach will check for expected fields in both paths before determine which path houses the comments themselves.

lib/app.js

@@ -160,7 +160,7 @@ const MAPPINGS = {
   },
   recentChanges: ['ds:5', 1, 2, 144, 1, 1],
   comments: {
-    path: ['ds:8', 0],
+    path: [],
     isArray: true,
     fun: helper.extractComments
   },

lib/utils/mappingHelpers.js

@@ -47,9 +47,46 @@ function buildHistogram (container) {
  * Extract the comments from google play script array
  * @param {array} comments The comments array
  */
-function extractComments (comments) {
-  if (!comments) return [];
-  return comments.map(R.path([4])).slice(0, 5);
+function extractComments (data) {
+  /**
+   * Comments have been found to migrate between two
+   * paths: ds:8 and ds:9. For this reason, we'll check
+   * for expected fields in both paths to determine
+   * the correct path to use.
+   */
+  let comments = [];
+
+  for (const path of ['ds:8', 'ds:9']) {
+    const authorPath = [path, 0, 0, 1, 0];
+    const versionPath = [path, 0, 0, 10];
+    const datePath = [path, 0, 0, 5, 0];
+
+    /**
+     * This logic could be further improved by checking
+     * values like `version` and `date` against expected
+     * patterns for these values.
+     */
+    if (R.path(authorPath, data)) {
+      if (R.path(versionPath, data)) {
+        if (R.path(datePath, data)) {
+          /**
+           * If we have found all expected fields, then
+           * we will dump the original comments structure
+           * into the `comments` variable for further
+           * handling.
+           */
+          comments = R.path([path, 0], data);
+          break;
+        }
+      }
+    }
+  }
+
+  if (comments.length > 0) {
+    comments = comments.map(R.path([4])).slice(0, 5);
+  }
+
+  return comments;
 }
 
 function extractFeatures (featuresArray) {