Refresh on the pdf preview page gives 404

[minump]

Refresh on the pdf preview page gives 404 - this is expected as pdf is not stored in browser. But as you pointed out, it would be nice to have a note mentioning not to refresh.

When you hit refresh when in /preview page, the error is as below

Not Found
404
NotFoundError: Not Found
    at /app/app.js:164:8
    at Layer.handle [as handle_request] (/app/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/app/node_modules/express/lib/router/index.js:317:13)
    at /app/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/app/node_modules/express/lib/router/index.js:335:12)
    at next (/app/node_modules/express/lib/router/index.js:275:10)
    at /app/node_modules/express/lib/router/index.js:635:15
    at next (/app/node_modules/express/lib/router/index.js:260:14)
    at Function.handle (/app/node_modules/express/lib/router/index.js:174:3)
    at router (/app/node_modules/express/lib/router/index.js:47:12)

[minump]

app.use('/preview',express.static('../dist')); // test this in server/app.js