settings_bots: Extract logic for ability to create bots.

This is a minor refactor/deduplication and renaming of
'admin_only_bot_creation' to 'can_create_new_bots'

frontend_tests/node_tests/settings_bots.js

@@ -195,3 +195,15 @@ run_test('test tab clicks', () => {
         assert(forms.inactive.visible());
     }());
 });
+
+run_test('can_create_new_bots', () => {
+    page_params.is_admin = true;
+    assert(settings_bots.can_create_new_bots());
+
+    page_params.is_admin = false;
+    page_params.realm_bot_creation_policy = 1;
+    assert(settings_bots.can_create_new_bots());
+
+    page_params.realm_bot_creation_policy = 3;
+    assert(!settings_bots.can_create_new_bots());
+});

static/js/settings.js

@@ -136,9 +136,7 @@ exports.setup_page = function () {
         zuliprc: 'zuliprc',
         botserverrc: 'botserverrc',
         timezones: moment.tz.names(),
-        admin_only_bot_creation: page_params.is_admin ||
+        can_create_new_bots: settings_bots.can_create_new_bots(),
-            page_params.realm_bot_creation_policy !==
-            settings_bots.bot_creation_policy_values.admins_only.code,
         settings_label: settings.settings_label,
     });
 

static/js/settings_bots.js

@@ -72,8 +72,7 @@ function render_bots() {
         user_owns_an_active_bot = user_owns_an_active_bot || elem.is_active;
     });
 
-    if (page_params.is_admin || page_params.realm_bot_creation_policy !==
+    if (settings_bots.can_create_new_bots()) {
-        exports.bot_creation_policy_values.admins_only.code) {
         if (!user_owns_an_active_bot) {
             focus_tab.add_a_new_bot_tab();
             return;
@@ -146,6 +145,15 @@ exports.bot_creation_policy_values = {
     },
 };
 
+exports.can_create_new_bots = function () {
+    if (page_params.is_admin) {
+        return true;
+    }
+
+    return page_params.realm_bot_creation_policy !==
+        exports.bot_creation_policy_values.admins_only.code;
+};
+
 exports.update_bot_settings_tip = function () {
     var permission_type = exports.bot_creation_policy_values;
     var current_permission = page_params.realm_bot_creation_policy;
@@ -164,9 +172,7 @@ exports.update_bot_permissions_ui = function () {
     exports.update_bot_settings_tip();
     $('#bot_table_error').hide();
     $("#id_realm_bot_creation_policy").val(page_params.realm_bot_creation_policy);
-    if (page_params.realm_bot_creation_policy ===
+    if (!exports.can_create_new_bots()) {
-        exports.bot_creation_policy_values.admins_only.code &&
-        !page_params.is_admin) {
         $('#create_bot_form').hide();
         $('.add-a-new-bot-tab').hide();
         focus_tab.active_bots_tab();

static/templates/settings/bot-settings.handlebars

@@ -15,7 +15,7 @@
         <ul class="nav nav-tabs nav-justified" id="bots_lists_navbar">
             <li class="active active-bots-tab"><a>{{t "Active bots" }}</a></li>
             <li class="inactive-bots-tab"><a>{{t "Inactive bots" }}</a></li>
-            <li class="add-a-new-bot-tab {{#unless admin_only_bot_creation}}hide{{/unless}}"><a>{{t "Add a new bot" }}</a></li>
+            <li class="add-a-new-bot-tab {{#unless can_create_new_bots}}hide{{/unless}}"><a>{{t "Add a new bot" }}</a></li>
         </ul>
 
         <ol class="bots_list required-text" id="active_bots_list" data-empty="{{t 'You have no active bots.' }}">
@@ -28,7 +28,7 @@
 
         <div id="add-a-new-bot-form">
             <form id="create_bot_form"
-              class="form-horizontal no-padding {{#unless admin_only_bot_creation}}hide{{/unless}}">
+              class="form-horizontal no-padding {{#unless can_create_new_bots}}hide{{/unless}}">
                 <div class="new-bot-form">
                     <div class="input-group">
                         <label for="bot_type">