Change let -> var, solves #838

src/shared/dom.js

@@ -104,7 +104,7 @@ export function toNumber(value) {
 
 export function timeRangesToArray(ranges) {
 	var array = [];
-	for (let i = 0; i < ranges.length; i += 1) {
+	for (var i = 0; i < ranges.length; i += 1) {
 		array.push({ start: ranges.start(i), end: ranges.end(i) });
 	}
 	return array;

test/js/samples/media-bindings/expected-bundle.js

@@ -35,7 +35,7 @@ function removeListener(node, event, handler) {
 
 function timeRangesToArray(ranges) {
 	var array = [];
-	for (let i = 0; i < ranges.length; i += 1) {
+	for (var i = 0; i < ranges.length; i += 1) {
 		array.push({ start: ranges.start(i), end: ranges.end(i) });
 	}
 	return array;