I'm getting a 'Promise' is undefined error in IE. Why is that and how can I solve this?
Add something like
<script src="https://cdnjs.cloudflare.com/ajax/libs/bluebird/3.3.5/bluebird.min.js"></script>
To <head>...</head>
This will pull in an external Bluebird Promise Library, so that you will be able to use Promise on IE
来源：https://stackoverflow.com/questions/36831372/promise-is-undefined-in-ie