diff --git a/static/js/composebox_typeahead.js b/static/js/composebox_typeahead.js
index 8ebc4c2e47..8579d07f74 100644
--- a/static/js/composebox_typeahead.js
+++ b/static/js/composebox_typeahead.js
@@ -183,6 +183,127 @@ exports.split_at_cursor = function (query) {
     return [query.slice(0, cursor), query.slice(cursor)];
 };
 
+exports.compose_content_begins_typeahead = function (query) {
+    var q = exports.split_at_cursor(query)[0];
+
+    var strings = q.split(/[\s*(){}\[\]]/);
+    if (strings.length < 1) {
+        return false;
+    }
+    var current_token = strings[strings.length-1];
+
+    // Only start the emoji autocompleter if : is directly after one
+    // of the whitespace or punctuation chars we split on.
+    if (current_token[0] === ':') {
+        // We don't want to match non-emoji emoticons such
+        // as :P or :-p
+        // Also, if the user has only typed a colon and nothing after,
+        // no need to match yet.
+        if (/^:-?.?$/.test(current_token)) {
+            return false;
+        }
+        this.completing = 'emoji';
+        this.token = current_token.substring(1);
+        return emoji.emojis;
+    }
+
+    // Don't autocomplete more than this many characters.
+    var max_chars = 30;
+    var last_at = q.lastIndexOf('@');
+    if (last_at === -1 || last_at < q.length-1 - max_chars) {
+        return false;  // No '@', or too far back
+    }
+
+    // Only match if the @ follows a space, various punctuation,
+    // or is at the beginning of the string.
+    if (last_at > 0 && "\n\t \"'(){}[]".indexOf(q[last_at-1]) === -1) {
+        return false;
+    }
+
+    current_token = q.substring(last_at + 1);
+    if (current_token.length < 1 || current_token.lastIndexOf('*') !== -1) {
+        return false;
+    }
+
+    this.completing = 'mention';
+    this.token = current_token.substring(current_token.indexOf("@")+1);
+    var all_item = {
+        special_item_text: "all (Notify everyone)",
+        email: "all",
+        // Always sort above, under the assumption that names will
+        // be longer and only contain "all" as a substring.
+        pm_recipient_count: Infinity,
+        full_name: "all"
+    };
+    return page_params.people_list.concat([all_item]);
+};
+
+exports.content_highlighter = function (item) {
+    if (this.completing === 'emoji') {
+        return "<img class='emoji' src='" + item.emoji_url + "' /> " + item.emoji_name;
+    } else if (this.completing === 'mention') {
+        var item_formatted = typeahead_helper.render_person(item);
+        return typeahead_helper.highlight_with_escaping(this.token, item_formatted);
+    }
+};
+
+exports.content_typeahead_selected = function (item) {
+    var pieces = exports.split_at_cursor(this.query);
+    var beginning = pieces[0];
+    var rest = pieces[1];
+
+    if (this.completing === 'emoji') {
+        //leading and trailing spaces are required for emoji, except if it begins a message.
+        if (beginning.lastIndexOf(":") === 0 || beginning.charAt(beginning.lastIndexOf(":") - 1) === " ") {
+            beginning = beginning.replace(/:\S+$/, "") + ":" + item.emoji_name + ": ";
+        } else {
+            beginning = beginning.replace(/:\S+$/, "") + " :" + item.emoji_name + ": ";
+        }
+    } else if (this.completing === 'mention') {
+        beginning = (beginning.substring(0, beginning.length - this.token.length-1)
+                + '@**' + item.full_name + '** ');
+
+        // We insert a special `all` item to the autocompleter above
+        // Don't consider it a user mention
+        if (item.email !== 'all') {
+            $(document).trigger('usermention_completed.zulip', {mentioned: item});
+        }
+    }
+
+    // Keep the cursor after the newly inserted text, as Bootstrap will call textbox.change() to overwrite the text
+    // in the textbox.
+    setTimeout(function () {
+        $('#new_message_content').caret(beginning.length, beginning.length);
+    }, 0);
+    return beginning + rest;
+};
+
+exports.initialize_compose_typeahead = function (selector) {
+    $(selector).typeahead({
+        items: 5,
+        dropup: true,
+        fixed: true,
+        source: exports.compose_content_begins_typeahead,
+        highlighter: exports.content_highlighter,
+        matcher: function (item) {
+            if (this.completing === 'emoji') {
+                return query_matches_emoji(this.token, item);
+            } else if (this.completing === 'mention') {
+                return query_matches_person(this.token, item);
+            }
+        },
+        sorter: function (matches) {
+            if (this.completing === 'emoji') {
+                return typeahead_helper.sort_emojis(matches, this.token);
+            } else if (this.completing === 'mention') {
+                return typeahead_helper.sort_recipients(matches, this.token);
+            }
+        },
+        updater: exports.content_typeahead_selected,
+        stopAdvance: true // Do not advance to the next field on a tab or enter
+    });
+};
+
 exports.initialize = function () {
     select_on_focus("stream");
     select_on_focus("subject");
@@ -286,118 +407,7 @@ exports.initialize = function () {
         stopAdvance: true // Do not advance to the next field on a tab or enter
     });
 
-    $( "#new_message_content" ).typeahead({
-        source: function (query, process) {
-            var q = exports.split_at_cursor(query)[0];
-
-            var strings = q.split(/[\s*(){}\[\]]/);
-            if (strings.length < 1) {
-                return false;
-            }
-            var current_token = strings[strings.length-1];
-
-            // Only start the emoji autocompleter if : is directly after one
-            // of the whitespace or punctuation chars we split on.
-            if (current_token[0] === ':') {
-                // We don't want to match non-emoji emoticons such
-                // as :P or :-p
-                // Also, if the user has only typed a colon and nothing after,
-                // no need to match yet.
-                if (/^:-?.?$/.test(current_token)) {
-                    return false;
-                }
-                this.completing = 'emoji';
-                this.token = current_token.substring(1);
-                return emoji.emojis;
-            }
-
-            // Don't autocomplete more than this many characters.
-            var max_chars = 30;
-            var last_at = q.lastIndexOf('@');
-            if (last_at === -1 || last_at < q.length-1 - max_chars) {
-                return false;  // No '@', or too far back
-            }
-
-            // Only match if the @ follows a space, various punctuation,
-            // or is at the beginning of the string.
-            if (last_at > 0 && "\n\t \"'(){}[]".indexOf(q[last_at-1]) === -1) {
-                return false;
-            }
-
-            current_token = q.substring(last_at + 1);
-            if (current_token.length < 1 || current_token.lastIndexOf('*') !== -1) {
-                return false;
-            }
-
-            this.completing = 'mention';
-            this.token = current_token.substring(current_token.indexOf("@")+1);
-            var all_item = {
-                special_item_text: "all (Notify everyone)",
-                email: "all",
-                // Always sort above, under the assumption that names will
-                // be longer and only contain "all" as a substring.
-                pm_recipient_count: Infinity,
-                full_name: "all"
-            };
-            return page_params.people_list.concat([all_item]);
-        },
-        items: 5,
-        highlighter: function (item) {
-            if (this.completing === 'emoji') {
-                return "<img class='emoji' src='" + item.emoji_url + "' /> " + item.emoji_name;
-            } else if (this.completing === 'mention') {
-                var item_formatted = typeahead_helper.render_person(item);
-                return typeahead_helper.highlight_with_escaping(this.token, item_formatted);
-            }
-        },
-        dropup: true,
-        fixed: true,
-        matcher: function (item) {
-            if (this.completing === 'emoji') {
-                return query_matches_emoji(this.token, item);
-            } else if (this.completing === 'mention') {
-                return query_matches_person(this.token, item);
-            }
-        },
-        sorter: function (matches) {
-            if (this.completing === 'emoji') {
-                return typeahead_helper.sort_emojis(matches, this.token);
-            } else if (this.completing === 'mention') {
-                return typeahead_helper.sort_recipients(matches, this.token);
-            }
-        },
-        updater: function (item) {
-            var pieces = exports.split_at_cursor(this.query);
-            var beginning = pieces[0];
-            var rest = pieces[1];
-
-            if (this.completing === 'emoji') {
-                //leading and trailing spaces are required for emoji, except if it begins a message.
-                if (beginning.lastIndexOf(":") === 0 || beginning.charAt(beginning.lastIndexOf(":") - 1) === " ") {
-                    beginning = beginning.replace(/:\S+$/, "") + ":" + item.emoji_name + ": ";
-                } else {
-                    beginning = beginning.replace(/:\S+$/, "") + " :" + item.emoji_name + ": ";
-                }
-            } else if (this.completing === 'mention') {
-                beginning = (beginning.substring(0, beginning.length - this.token.length-1)
-                        + '@**' + item.full_name + '** ');
-
-                // We insert a special `all` item to the autocompleter above
-                // Don't consider it a user mention
-                if (item.email !== 'all') {
-                    $(document).trigger('usermention_completed.zulip', {mentioned: item});
-                }
-            }
-
-            // Keep the cursor after the newly inserted text, as Bootstrap will call textbox.change() to overwrite the text
-            // in the textbox.
-            setTimeout(function () {
-                $('#new_message_content').caret(beginning.length, beginning.length);
-            }, 0);
-            return beginning + rest;
-        },
-        stopAdvance: true // Do not advance to the next field on a tab or enter
-    });
+    exports.initialize_compose_typeahead("#new_message_content");
 
     $( "#private_message_recipient" ).blur(function (event) {
         var val = $(this).val();