Initial work on showing all options on @

spec/autocomplete.js

@@ -100,7 +100,7 @@
                     'target': textarea,
                     'preventDefault': _.noop,
                     'stopPropagation': _.noop,
-                    'keyCode': 13
+                    'keyCode': 13 // Enter
                 });
                 expect(textarea.value).toBe('hello s some2');
 
@@ -123,6 +123,18 @@
                 view.keyPressed(tab_event);
                 view.keyUp(tab_event);
                 expect(textarea.value).toBe('hello z3r0');
+
+                // Test that pressing @ brings up all options
+                const at_event = {
+                    'target': textarea,
+                    'preventDefault': _.noop,
+                    'stopPropagation': _.noop,
+                    'keyCode': 50
+                };
+                view.keyPressed(at_event);
+                view.keyUp(at_event);
+                textarea.value = 'hello z3r0 and @';
+
                 done();
             }).catch(_.partial(console.error, _));
         }));

src/converse-autocomplete.js

@@ -74,6 +74,7 @@
                     _.assignIn(this, {
                         'match_current_word': false, // Match only the current word, otherwise all input is matched
                         'match_on_tab': false, // Whether matching should only start when tab's pressed
+                        'trigger_on_at': false, // Whether @ should trigger autocomplete
                         'min_chars': 2,
                         'max_items': 10,
                         'auto_evaluate': true,
@@ -294,6 +295,8 @@
                     if (this.match_on_tab && ev.keyCode === _converse.keycodes.TAB) {
                         ev.preventDefault();
                         this.auto_completing = true;
+                    } else if (this.trigger_on_at && ev.keyCode === _converse.keycodes.AT) {
+                        this.auto_completing = true;
                     }
                 }
 
@@ -312,7 +315,11 @@
                     } 
 
                     const list = typeof this._list === "function" ? this._list() : this._list;
-                    if (value.length >= this.min_chars && list.length > 0) {
+                    if (list.length > 0 && (
+                                (value.length >= this.min_chars) ||
+                                (this.trigger_on_at && ev.keyCode === value.startsWith('@'))
+                            )) {
+
                         this.index = -1;
                         // Populate list with options that match
                         this.ul.innerHTML = "";

src/converse-core.js

@@ -117,6 +117,7 @@
         UP_ARROW: 38,
         DOWN_ARROW: 40,
         FORWARD_SLASH: 47,
+        AT: 50,
         META: 91,
         META_RIGHT: 93
     };

src/converse-muc-views.js

@@ -618,7 +618,8 @@
                         'match_current_word': true,
                         'match_on_tab': true,
                         'list': () => this.model.occupants.map(o => ({'label': o.get('nick'), 'value': o.get('nick')})),
-                        'filter': _converse.FILTER_STARTSWITH
+                        'filter': _converse.FILTER_STARTSWITH,
+                        'trigger_on_at': true
                     });
                     this.auto_complete.on('suggestion-box-selectcomplete', () => (this.auto_completing = false));
                 },