add explicit error for lack of tether in tooltips - fixes #17273

dist/js/bootstrap.js

@@ -2764,6 +2764,14 @@ var Tab = (function ($) {
 
 var Tooltip = (function ($) {
 
+  /**
+   * Check for Tether dependency
+   * Tether - http://github.hubspot.com/tether/
+   */
+  if (!window.Tether) {
+    throw new Error("Bootstrap tooltips require Tether (http://github.hubspot.com/tether/)");
+  }
+
   /**
    * ------------------------------------------------------------------------
    * Constants

dist/js/umd/tooltip.js

@@ -32,6 +32,14 @@
 
   var Tooltip = (function ($) {
 
+    /**
+     * Check for Tether dependency
+     * Tether - http://github.hubspot.com/tether/
+     */
+    if (!window.Tether) {
+      throw new Error("Bootstrap tooltips require Tether (http://github.hubspot.com/tether/)");
+    }
+
     /**
      * ------------------------------------------------------------------------
      * Constants

js/dist/tooltip.js

@@ -15,6 +15,14 @@ function _classCallCheck(instance, Constructor) { if (!(instance instanceof Cons
 
 var Tooltip = (function ($) {
 
+  /**
+   * Check for Tether dependency
+   * Tether - http://github.hubspot.com/tether/
+   */
+  if (!window.Tether) {
+    throw new Error("Bootstrap tooltips require Tether (http://github.hubspot.com/tether/)");
+  }
+
   /**
    * ------------------------------------------------------------------------
    * Constants

js/src/tooltip.js

@@ -12,6 +12,14 @@ import Util from './util'
 
 const Tooltip = (($) => {
 
+  /**
+   * Check for Tether dependency
+   * Tether - http://github.hubspot.com/tether/
+   */
+  if (!window.Tether) {
+    throw new Error('Bootstrap tooltips require Tether (http://github.hubspot.com/tether/)')
+  }
+
 
   /**
    * ------------------------------------------------------------------------