Switch to modern syntax in copy.js

source/javascripts/copy.js

@@ -1,48 +1,45 @@
-(function () {
-  function Copy($module) {
-    this.$module = $module
-  }
-
-  Copy.prototype.init = function () {
-    var $module = this.$module
-
-    if (!$module) {
-      return
+(() => {
+  class Copy {
+    constructor($module) {
+      this.$module = $module
     }
 
-    // Bail if no clipboard support (e.g. IE11)
-    if (!navigator.clipboard) {
-      return;
-    }
+    init() {
+      // Bail if no clipboard support (e.g. IE11)
+      if (!navigator.clipboard) {
+        return;
+      }
 
-    var $button = document.createElement('button')
-    $button.className = 'app-copy-button js-copy-button'
-    $button.setAttribute('aria-live', 'assertive')
-    $button.textContent = 'Copy code'
+      const $button = document.createElement('button');
 
-    $module.insertAdjacentElement('beforebegin', $button)
+      $button.className = 'app-copy-button js-copy-button';
+      $button.setAttribute('aria-live', 'assertive');
+      $button.textContent = 'Copy code';
 
-    $button.addEventListener('click', this.handleCopy)
-  }
+      this.$module.insertAdjacentElement('beforebegin', $button);
+
+      $button.addEventListener('click', this.handleCopy);
+    }
 
-  Copy.prototype.handleCopy = function (event) {
-    var target = event.target.nextElementSibling;
+    handleCopy(event){
+      const target = event.target.nextElementSibling;
 
-    navigator.clipboard.writeText(target.textContent)
-      .then(function () {
-        event.target.textContent = 'Code copied';
+      navigator.clipboard.writeText(target.textContent)
+        .then(() => {
+          event.target.textContent = 'Code copied';
 
-        setTimeout(function () {
-          event.target.textContent = 'Copy code';
-        }, 5000);
-      })
-      .catch(function (err) {
-        console.error(err);
-      })
+          setTimeout(() => {
+            event.target.textContent = 'Copy code';
+          }, 5000);
+        })
+        .catch((err) => {
+          console.error(err);
+        })
+    }
   }
 
   document.querySelectorAll('pre.highlight')
-    .forEach(function ($el) {
+    .forEach(($el) => {
       new Copy($el).init();
     });
 })();