Added selector support for "set"

Author: rinodrummer

src/slideshow.js

@@ -296,7 +296,7 @@ function Slideshow({container = '#slideshow', slideshowSelector = '.slideshow',
     /**
      * Sets the current slide.
      *
-     * @param   {number|HTMLElement|Node}   slide   Index of the element or the
+     * @param   {string|number|HTMLElement|Node}   slide   Index of the element or the
      *                                          element itself to bet setted as
      *                                          current.
      *
@@ -311,7 +311,11 @@ function Slideshow({container = '#slideshow', slideshowSelector = '.slideshow',
      */
     this.set = (slide) => {
         if (slide == null) {
-            throw new Error('The given element is not a valid value. Please, insert an integer or a DOM element.');
+            throw new Error('The given element is not a valid value. Please, insert a string, an integer or a DOM element.');
+        }
+
+        if (typeof slide === 'string') {
+            slide = document.querySelector(slide);
         }
 
         if (typeof slide === 'number') {
@@ -332,7 +336,7 @@ function Slideshow({container = '#slideshow', slideshowSelector = '.slideshow',
             }
         }
         else {
-            throw new Error('The given element is not a valid value. Please, insert an integer or a DOM element.');
+            throw new Error('The given element is not a valid value. Please, insert a string, an integer or a DOM element.');
         }
 
         const oldCurrent = current;