hotkeys: Add "p" to narrow to next unread PM thread.

This works simimlar to the "n" key for next topics.

This commit does a few things:

    * It wires up the hotkey to an existing function
      that could change narrows.
    * It adds documentation.
    * It adds logic to make sure the compose box does
      not open.

@showell helped a bit with the wording of comments here.

Fixes #4874

frontend_tests/node_tests/hotkey.js

@@ -148,7 +148,7 @@ function stubbing(func_name_to_stub, test_function) {
 
     // Unmapped keys should immediately return false, without
     // calling any functions outside of hotkey.js.
-    assert_unmapped('abefhlmoptxyz');
+    assert_unmapped('abefhlmotxyz');
     assert_unmapped('BEFHILNOQTUWXYZ');
 
     // We have to skip some checks due to the way the code is
@@ -286,6 +286,7 @@ function stubbing(func_name_to_stub, test_function) {
     // Test keys that work when a message is selected and
     // also when the message list is empty.
     assert_mapping('n', 'narrow.narrow_to_next_topic');
+    assert_mapping('p', 'narrow.narrow_to_next_pm_string');
 
     global.current_msg_list.empty = return_true;
     assert_mapping('n', 'narrow.narrow_to_next_topic');

static/js/compose_actions.js

@@ -384,7 +384,17 @@ exports.quote_and_reply = function (opts) {
     });
 };
 
-exports.on_narrow = function () {
+exports.on_narrow = function (opts) {
+    // We use force_close when jumping between PM narrows with the "p" key,
+    // so that we don't have an open compose box that makes it difficult
+    // to cycle quickly through unread messages.
+    if (opts.force_close) {
+        // This closes the compose box if it was already open, and it is
+        // basically a noop otherwise.
+        exports.cancel();
+        return;
+    }
+
     if (narrow_state.narrowed_by_topic_reply()) {
         exports.on_topic_narrow();
         return;

static/js/hotkey.js

@@ -94,6 +94,7 @@ var keypress_mappings = {
     106: {name: 'vim_down', message_view_only: true}, // 'j'
     107: {name: 'vim_up', message_view_only: true}, // 'k'
     110: {name: 'n_key', message_view_only: false}, // 'n'
+    112: {name: 'p_key', message_view_only: false}, // 'p'
     113: {name: 'query_streams', message_view_only: false}, // 'q'
     114: {name: 'reply_message', message_view_only: true}, // 'r'
     115: {name: 'narrow_by_recipient', message_view_only: true}, // 's'
@@ -630,6 +631,9 @@ exports.process_hotkey = function (e, hotkey) {
         case 'n_key':
             narrow.narrow_to_next_topic();
             return true;
+        case 'p_key':
+            narrow.narrow_to_next_pm_string();
+            return true;
         case 'open_drafts':
             drafts.launch();
             return true;

static/js/narrow.js

@@ -248,7 +248,7 @@ exports.activate = function (raw_operators, opts) {
     $('#search_query').val(Filter.unparse(operators));
     search.update_button_visibility();
 
-    compose_actions.on_narrow();
+    compose_actions.on_narrow(opts);
 
     var current_filter = narrow_state.get_current_filter();
 
@@ -361,8 +361,8 @@ exports.narrow_to_next_topic = function () {
     exports.activate(filter_expr, opts);
 };
 
-
 exports.narrow_to_next_pm_string = function () {
+
     var curr_pm = narrow_state.pm_string();
 
     var next_pm = topic_generator.get_next_unread_pm_string(curr_pm);
@@ -379,8 +379,10 @@ exports.narrow_to_next_pm_string = function () {
         {operator: 'pm-with', operand: pm_with},
     ];
 
+    // force_close parameter is true to not auto open compose_box
     var opts = {
         select_first_unread: true,
+        force_close: true,
     };
 
     exports.activate(filter_expr, opts);

templates/zerver/help/keyboard-shortcuts.md

@@ -35,6 +35,8 @@ below, and add more to your repertoire as needed.
 
 * **Next unread topic**: `n`
 
+* **Next unread private message**: `p`
+
 * **All private messages**: `P`
 
 * **Search messages**: `/`
@@ -66,6 +68,8 @@ below, and add more to your repertoire as needed.
 
 * **Narrow to next unread topic**: `n`
 
+* **Narrow to next unread private message**: `p`
+
 * **Narrow to stream**: `s`
 
 * **Narrow to topic**: `S`

templates/zerver/keyboard_shortcuts.html

@@ -40,6 +40,10 @@
                     <td class="hotkey">n</td>
                     <td class="definition">{% trans %}Next unread topic{% endtrans %}</td>
                 </tr>
+                <tr>
+                    <td class="hotkey">p</td>
+                    <td class="definition">{% trans %}Next unread private message{% endtrans %}</td>
+                </tr>
                 <tr>
                     <td class="hotkey">P</td>
                     <td class="definition">{% trans %}All private messages{% endtrans %}</td>
@@ -170,6 +174,10 @@
                     <td class="hotkey">n</td>
                     <td class="definition">{% trans %}Narrow to next unread topic{% endtrans %}</td>
                 </tr>
+                <tr>
+                    <td class="hotkey">p</td>
+                    <td class="definition">{% trans %}Narrow to next unread private message{% endtrans %}</td>
+                </tr>
                 <tr>
                     <td class="hotkey">A, D</td>
                     <td class="definition">{% trans %}Cycle between stream narrows{% endtrans %}</td>