Fix Internet Explorer JS error on course outline

lms/static/js/ie11_find_array.js

@@ -47,3 +47,82 @@ if (!Array.prototype.find) {
         }
     });
 }
+
+// Production steps of ECMA-262, Edition 6, 22.1.2.1
+if (!Array.from) {
+    Array.from = (function () {
+        var toStr = Object.prototype.toString;
+        var isCallable = function (fn) {
+            return typeof fn === 'function' || toStr.call(fn) === '[object Function]';
+        };
+        var toInteger = function (value) {
+            var number = Number(value);
+            if (isNaN(number)) { return 0; }
+            if (number === 0 || !isFinite(number)) { return number; }
+            return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number));
+        };
+        var maxSafeInteger = Math.pow(2, 53) - 1;
+        var toLength = function (value) {
+            var len = toInteger(value);
+            return Math.min(Math.max(len, 0), maxSafeInteger);
+        };
+
+        // The length property of the from method is 1.
+        return function from(arrayLike/*, mapFn, thisArg */) {
+            // 1. Let C be the this value.
+            var C = this;
+
+            // 2. Let items be ToObject(arrayLike).
+            var items = Object(arrayLike);
+
+            // 3. ReturnIfAbrupt(items).
+            if (arrayLike == null) {
+                throw new TypeError('Array.from requires an array-like object - not null or undefined');
+            }
+
+            // 4. If mapfn is undefined, then let mapping be false.
+            var mapFn = arguments.length > 1 ? arguments[1] : void undefined;
+            var T;
+            if (typeof mapFn !== 'undefined') {
+                // 5. else
+                // 5. a If IsCallable(mapfn) is false, throw a TypeError exception.
+                if (!isCallable(mapFn)) {
+                    throw new TypeError('Array.from: when provided, the second argument must be a function');
+                }
+
+                // 5. b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+                if (arguments.length > 2) {
+                    T = arguments[2];
+                }
+            }
+
+            // 10. Let lenValue be Get(items, "length").
+            // 11. Let len be ToLength(lenValue).
+            var len = toLength(items.length);
+
+            // 13. If IsConstructor(C) is true, then
+            // 13. a. Let A be the result of calling the [[Construct]] internal method
+            // of C with an argument list containing the single item len.
+            // 14. a. Else, Let A be ArrayCreate(len).
+            var A = isCallable(C) ? Object(new C(len)) : new Array(len);
+
+            // 16. Let k be 0.
+            var k = 0;
+            // 17. Repeat, while k < len… (also steps a - h)
+            var kValue;
+            while (k < len) {
+                kValue = items[k];
+                if (mapFn) {
+                    A[k] = typeof T === 'undefined' ? mapFn(kValue, k) : mapFn.call(T, kValue, k);
+                } else {
+                    A[k] = kValue;
+                }
+                k += 1;
+            }
+            // 18. Let putStatus be Put(A, "length", len, true).
+            A.length = len;
+            // 20. Return A.
+            return A;
+        };
+    }());
+}