Move keep_pointer_in_view to pointer.js.

static/js/pointer.js

@@ -74,6 +74,79 @@ exports.fast_forward_pointer = function () {
         }
     });
 };
+
+exports.keep_pointer_in_view = function () {
+    // See recenter_view() for related logic to keep the pointer onscreen.
+    // This function mostly comes into place for mouse scrollers, and it
+    // keeps the pointer in view.  For people who purely scroll with the
+    // mouse, the pointer is kind of meaningless to them, but keyboard
+    // users will occasionally do big mouse scrolls, so this gives them
+    // a pointer reasonably close to the middle of the screen.
+    var candidate;
+    var next_row = current_msg_list.selected_row();
+
+    if (next_row.length === 0) {
+        return;
+    }
+
+    var info = viewport.message_viewport_info();
+    var top_threshold = info.visible_top + (1/10 * info.visible_height);
+    var bottom_threshold = info.visible_top + (9/10 * info.visible_height);
+
+    function message_is_far_enough_down() {
+        if (viewport.at_top()) {
+            return true;
+        }
+
+        var message_top = next_row.offset().top;
+
+        // If the message starts after the very top of the screen, we just
+        // leave it alone.  This avoids bugs like #1608, where overzealousness
+        // about repositioning the pointer can cause users to miss messages.
+        if (message_top >= info.visible_top) {
+            return true;
+        }
+
+
+        // If at least part of the message is below top_threshold (10% from
+        // the top), then we also leave it alone.
+        var bottom_offset = message_top + next_row.outerHeight(true);
+        if (bottom_offset >= top_threshold) {
+            return true;
+        }
+
+        // If we got this far, the message is not "in view."
+        return false;
+    }
+
+    function message_is_far_enough_up() {
+        return viewport.at_bottom() ||
+            (next_row.offset().top <= bottom_threshold);
+    }
+
+    function adjust(in_view, get_next_row) {
+        // return true only if we make an actual adjustment, so
+        // that we know to short circuit the other direction
+        if (in_view(next_row)) {
+            return false;  // try other side
+        }
+        while (!in_view(next_row)) {
+            candidate = get_next_row(next_row);
+            if (candidate.length === 0) {
+                break;
+            }
+            next_row = candidate;
+        }
+        return true;
+    }
+
+    if (!adjust(message_is_far_enough_down, rows.next_visible)) {
+        adjust(message_is_far_enough_up, rows.prev_visible);
+    }
+
+    current_msg_list.select_id(rows.id(next_row), {from_scroll: true});
+};
+
 return exports;
 }());
 if (typeof module !== 'undefined') {

static/js/ui.js

@@ -509,7 +509,7 @@ function scroll_finished() {
 
     if ($('#home').hasClass('active')) {
         if (!pointer.suppress_scroll_pointer_update) {
-            keep_pointer_in_view();
+            pointer.keep_pointer_in_view();
         } else {
             pointer.suppress_scroll_pointer_update = false;
         }

static/js/zulip.js

@@ -17,84 +17,12 @@ var queued_flag_timer;
 // positive means scroll down.
 var last_viewport_movement_direction = 1;
 
-function keep_pointer_in_view() {
-    // See recenter_view() for related logic to keep the pointer onscreen.
-    // This function mostly comes into place for mouse scrollers, and it
-    // keeps the pointer in view.  For people who purely scroll with the
-    // mouse, the pointer is kind of meaningless to them, but keyboard
-    // users will occasionally do big mouse scrolls, so this gives them
-    // a pointer reasonably close to the middle of the screen.
-    var candidate;
-    var next_row = current_msg_list.selected_row();
-
-    if (next_row.length === 0) {
-        return;
-    }
-
-    var info = viewport.message_viewport_info();
-    var top_threshold = info.visible_top + (1/10 * info.visible_height);
-    var bottom_threshold = info.visible_top + (9/10 * info.visible_height);
-
-    function message_is_far_enough_down() {
-        if (viewport.at_top()) {
-            return true;
-        }
-
-        var message_top = next_row.offset().top;
-
-        // If the message starts after the very top of the screen, we just
-        // leave it alone.  This avoids bugs like #1608, where overzealousness
-        // about repositioning the pointer can cause users to miss messages.
-        if (message_top >= info.visible_top) {
-            return true;
-        }
-
-
-        // If at least part of the message is below top_threshold (10% from
-        // the top), then we also leave it alone.
-        var bottom_offset = message_top + next_row.outerHeight(true);
-        if (bottom_offset >= top_threshold) {
-            return true;
-        }
-
-        // If we got this far, the message is not "in view."
-        return false;
-    }
-
-    function message_is_far_enough_up() {
-        return viewport.at_bottom() ||
-            (next_row.offset().top <= bottom_threshold);
-    }
-
-    function adjust(in_view, get_next_row) {
-        // return true only if we make an actual adjustment, so
-        // that we know to short circuit the other direction
-        if (in_view(next_row)) {
-            return false;  // try other side
-        }
-        while (!in_view(next_row)) {
-            candidate = get_next_row(next_row);
-            if (candidate.length === 0) {
-                break;
-            }
-            next_row = candidate;
-        }
-        return true;
-    }
-
-    if (!adjust(message_is_far_enough_down, rows.next_visible)) {
-        adjust(message_is_far_enough_up, rows.prev_visible);
-    }
-
-    current_msg_list.select_id(rows.id(next_row), {from_scroll: true});
-}
-
 function recenter_view(message, opts) {
     opts = opts || {};
 
     // Barnowl-style recentering: if the pointer is too high, move it to
     // the 1/2 marks. If the pointer is too low, move it to the 1/7 mark.
-    // See keep_pointer_in_view() for related logic to keep the pointer onscreen.
+    // See keep_pointer_in_view() in pointer.js for related logic to keep the pointer onscreen.
 
     var viewport_info = viewport.message_viewport_info();
     var top_threshold = viewport_info.visible_top;

tools/jslint/check-all.js

@@ -54,7 +54,6 @@ var globals =
 
     // zulip.js
     + ' all_msg_list home_msg_list narrowed_msg_list current_msg_list'
-    + ' keep_pointer_in_view'
     + ' respond_to_message recenter_view last_viewport_movement_direction'
     + ' scroll_to_selected get_private_message_recipient'
     + ' process_loaded_for_unread'