The browser field exported by Turndown’s package.json apparently does not work as expected. When users want to build their project using Turndown and use it in browsers, the output contains JSDOM even though the JSDOM dependency is turned off in browser field. It's caused by using default module (i.e. turndown.es.js) which contains JSDOM. At this moment there is no way to use turndown.browser.*.js module variants which don't contain JSDOM.