Add polyfills for IE11

js/_init.js

@@ -6,13 +6,6 @@ document.onreadystatechange = () => {
     // The document has finished loading and the document has been parsed
     // but sub-resources such as images, stylesheets and frames are still loading.
     if (document.readyState === 'interactive') {
-        // Function to make IE9+ support forEach
-        // untested (CBD Free not working)
-        // https://stackoverflow.com/a/50917053/6850747
-        if (window.NodeList && !NodeList.prototype.forEach) {
-            NodeList.prototype.forEach = Array.prototype.forEach;
-        }
-
         document.querySelectorAll('.label[data-for]').forEach((label) => {
             const labelInstance = new Label({
                 instanceElement: label

js/_keyboard-helpers.js

@@ -244,6 +244,75 @@ class KeyboardHelpers {
         return keyboardNavigableElementIndex;
     }
 
+    /**
+     * @function initPolyfills
+     * @memberof KeyboardHelpers
+     */
+    initPolyfills() {
+        // Polyfill for forEach
+        if (window.NodeList && !NodeList.prototype.forEach) {
+            NodeList.prototype.forEach = Array.prototype.forEach;
+        }
+
+        // Polyfill for forEach
+        if (window.HTMLCollection && !HTMLCollection.prototype.forEach) {
+            HTMLCollection.prototype.forEach = Array.prototype.forEach;
+        }
+
+        // Polyfill for includes
+        // https://www.cluemediator.com/object-doesnt-support-property-or-method-includes-in-ie
+        if (!Array.prototype.includes) {
+            Object.defineProperty(Array.prototype, 'includes', {
+                value: function (searchElement, fromIndex) {
+
+                    if (this == null) {
+                        throw new TypeError('"this" is null or not defined');
+                    }
+
+                    // 1. Let O be ? ToObject(this value).
+                    var o = Object(this);
+
+                    // 2. Let len be ? ToLength(? Get(O, "length")).
+                    var len = o.length >>> 0;
+
+                    // 3. If len is 0, return false.
+                    if (len === 0) {
+                        return false;
+                    }
+
+                    // 4. Let n be ? ToInteger(fromIndex).
+                    //    (If fromIndex is undefined, this step produces the value 0.)
+                    var n = fromIndex | 0;
+
+                    // 5. If n ≥ 0, then
+                    //  a. Let k be n.
+                    // 6. Else n < 0,
+                    //  a. Let k be len + n.
+                    //  b. If k < 0, let k be 0.
+                    var k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);
+
+                    function sameValueZero(x, y) {
+                        return x === y || (typeof x === 'number' && typeof y === 'number' && isNaN(x) && isNaN(y));
+                    }
+
+                    // 7. Repeat, while k < len
+                    while (k < len) {
+                        // a. Let elementK be the result of ? Get(O, ! ToString(k)).
+                        // b. If SameValueZero(searchElement, elementK) is true, return true.
+                        if (sameValueZero(o[k], searchElement)) {
+                            return true;
+                        }
+                        // c. Increase k by 1. 
+                        k++;
+                    }
+
+                    // 8. Return false
+                    return false;
+                }
+            });
+        }
+    }
+
     /**
      * @function isComponentElement
      * @summary Determine whether the element is the instanceElement
@@ -578,6 +647,8 @@ class KeyboardHelpers {
      * @memberof KeyboardHelpers
      */
     init() {
+        this.initPolyfills();
+
         this.instanceId = this.instanceElement.getAttribute('id');
 
         this.registerKeyboardActions();