diff --git a/lib/jsdoc/src/parser.js b/lib/jsdoc/src/parser.js
index b776103db..6cdf3c317 100644
--- a/lib/jsdoc/src/parser.js
+++ b/lib/jsdoc/src/parser.js
@@ -219,7 +219,10 @@ Parser.prototype.parseExtra = function(filename, info) {
     var name = info.name.replace('exports.', '');
 
     this._extras[filename] = this._extras[filename] || {};
-    this._extras[filename][name] = this._extras[filename][name] || [];
+    const extrasArr = this._extras[filename][name] || [];
+    this._extras[filename][name] = extrasArr && !Array.isArray(extrasArr)
+        ? [extrasArr]
+        : extrasArr
 
     var ts = removeTSParenthesizedType(info.extra);