default to all fields for undefined `headers.fields` for fetch()

README.md

@@ -564,13 +564,13 @@ Valid `options` are:
 
   * **headers** - < _mixed_ > - An _array_ of specific headers to retrieve, _boolean_ true to fetch all headers, or an _object_ of the form (**Default:** (no headers)):
 
-      * **fields** - < _mixed_ > - An _array_ of specific headers to retrieve or _boolean_ true to fetch all headers.
+      * **fields** - < _mixed_ > - An _array_ of specific headers to retrieve or _boolean_ true to fetch all headers. **Default:** (all headers)
 
       * **parse** - < _boolean_ > - Parse headers? **Default:** true
 
   * **headersNot** - < _mixed_ > - An _array_ of specific headers to exclude or an _object_ of the form (**Default:** (no headers)):
 
-      * **fields** - < _mixed_ > - An _array_ of specific headers to exclude.
+      * **fields** - < _mixed_ > - An _array_ of specific headers to exclude. **Default:** (all headers)
 
       * **parse** - < _boolean_ > - Parse headers? **Default:** true
 

lib/imap.js

@@ -996,6 +996,8 @@ ImapConnection.prototype._fetch = function(which, uids, options, what, cb) {
           if (Array.isArray(wp.headers))
             headers = wp.headers;
           else if (typeof wp.headers === 'object') {
+            if (wp.headers.fields === undefined)
+              wp.headers.fields = true;
             if (!Array.isArray(wp.headers.fields)
                 && typeof wp.headers.fields !== 'string'
                 && wp.headers.fields !== true)
@@ -1026,6 +1028,8 @@ ImapConnection.prototype._fetch = function(which, uids, options, what, cb) {
           if (Array.isArray(wp.headersNot))
             headers = wp.headersNot;
           else if (typeof wp.headersNot === 'object') {
+            if (wp.headersNot.fields === undefined)
+              wp.headersNot.fields = true;
             if (!Array.isArray(wp.headersNot.fields)
                 && typeof wp.headersNot.fields !== 'string'
                 && wp.headersNot.fields !== true)