import jsdom from 'jsdom' const doc = jsdom.jsdom('') const win = doc.defaultView global.document = doc global.window = win // take all properties of the window object and also attach it to the // mocha global object propagateToGlobal(win) // from mocha-jsdom https://github.com/rstacruz/mocha-jsdom/blob/master/index.js#L80 function propagateToGlobal (window) { for (let key in window) { if (!window.hasOwnProperty(key)) continue if (key in global) continue global[key] = window[key] } }