From e08bbdf4f9a344f228dca2123adeb83034435b33 Mon Sep 17 00:00:00 2001
From: Ori Livneh <ori@wikimedia.org>
Date: Tue, 9 Dec 2014 21:13:44 -0800
Subject: [PATCH] Stash edit when user idles

Try to anticipate edit submissions earlier by looking for pauses in keyboard
input, on the assumption that users often take a few moments to look over an
edit before submitting it to the server.

Change-Id: Ib2de3f15b93e5d32c66a03363e98606412d5d53b
---
 .../mediawiki.action.edit.stash.js            | 44 ++++++++++++++++---
 1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/resources/src/mediawiki.action/mediawiki.action.edit.stash.js b/resources/src/mediawiki.action/mediawiki.action.edit.stash.js
index 9972321e47..9b8a0ceb81 100644
--- a/resources/src/mediawiki.action/mediawiki.action.edit.stash.js
+++ b/resources/src/mediawiki.action/mediawiki.action.edit.stash.js
@@ -3,10 +3,16 @@
  */
 ( function ( mw, $ ) {
 	$( function () {
-		var api = new mw.Api(), pending = null, $form = $( '#editform' );
+		var idleTimeout = 5000,
+			api = new mw.Api(),
+			pending = null,
+			$form = $( '#editform' ),
+			$text = $form.find( '#wpTextbox1' ),
+			data = {},
+			timer = null;
 
 		function stashEdit( token ) {
-			var data = $form.serializeObject();
+			data = $form.serializeObject();
 
 			pending = api.post( {
 				action: 'stashedit',
@@ -21,15 +27,42 @@
 			} );
 		}
 
+		/* Has the edit body text changed since the last stashEdit() call? */
+		function isChanged() {
+			// Normalize line endings to CRLF, like $.fn.serializeObject does.
+			var newText = $text.val().replace( /\r?\n/g, '\r\n' );
+			return newText !== data.wpTextbox1;
+		}
+
 		function onEditChanged() {
-			// If a stash request is already in flight, abort it, since its
-			// payload has just been invalidated by this change.
+			if ( !isChanged() ) {
+				return;
+			}
+
+			// If a request is in progress, abort it; its payload is stale.
 			if ( pending ) {
 				pending.abort();
 			}
+
 			api.getToken( 'edit' ).then( stashEdit );
 		}
 
+		function onKeyPress( e ) {
+			// Ignore keystrokes that don't modify text, like cursor movements.
+			// See <http://stackoverflow.com/q/2284844>.
+			if ( e.which === 0 ) {
+				return;
+			}
+
+			clearTimeout( timer );
+
+			if ( pending ) {
+				pending.abort();
+			}
+
+			timer = setTimeout( onEditChanged, idleTimeout );
+		}
+
 		// We don't attempt to stash new section edits because in such cases
 		// the parser output varies on the edit summary (since it determines
 		// the new section's name).
@@ -37,6 +70,7 @@
 			return;
 		}
 
-		$form.find( '#wpTextbox1' ).on( 'change', onEditChanged );
+		$text.on( { change: onEditChanged, keypress: onKeyPress } );
+
 	} );
 }( mediaWiki, jQuery ) );
-- 
2.20.1