import browserEnv from 'browser-env' browserEnv(['window', 'document', 'navigator']) // for CodeMirror mockup document.body.createTextRange = function () { return { setEnd: function () {}, setStart: function () {}, getBoundingClientRect: function () { return {right: 0} }, getClientRects: function () { return { length: 0, left: 0, right: 0 } } } } window.localStorage = { // polyfill getItem () { return '{}' } }