Uncaught SyntaxError: Use of future reserved word in strict mode

[vp2177]

When upgrading from 1.38.0 to 1.39.0, app no longer works:

Uncaught SyntaxError: Use of future reserved word in strict mode

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

This is because let is emitted in timeRangesToArray()

[Rich-Harris]

Thanks — released 1.39.1 and added a check to make sure this doesn't happen again