This is a duplicated question of the one asked on StackOverflow. I answered it there.
https://stackoverflow.com/questions/58851407/how-to-include-helpers-in-jsreport/58883252#58883252

Please don't post questions duplicates. Choose forum or so, what you prefer, and ask just once.

Hm, there is a 20s default timeout that .net waits for jsreport to start. Maybe it just doesn't finish start in time.
Please try to increase this timeout

In c# it would be like this. Note you need to have the latest jsreport.Local to have the StartTimeout exposed.

var rs = new LocalReporting()             
                .KillRunningJsReportProcesses()
                .UseBinary(JsReportBinary.GetBinary())              
                .AsWebServer()                
                .Create();

rs.StartTimeout = new TimeSpan(0,0,60);                        
rs.StartAsync().Wait();

The jsreport@2.6.1 was released before jsreport-docx@2.4.0.

The next jsreport release will get the deps updated.
Until then you can do

npm i jsreport-docx@2.4.0 --save

Hm. This looks like some kind of strange playground/jsreportonline bug.
The same works for me on my local jsreport.
You just click download in studio or sent request from postman and you get the modified content disposition and file name.

The workaround for playground/jsreportonline is using afterRender hook
https://playground.jsreport.net/w/anon/ozORijeq

function afterRender(req, res) {
  res.meta.reportName = 'aaa'
}

Thank you for your request.
I am afraid it isn't possible to set custom status code from script at this moment.
I've submitted this feature request to the github
https://github.com/jsreport/jsreport/issues/653
It is quite a quick win so we likely make sure it is ready in the next release.

Something like this could work

function findSomething(root, id) {
  return root.items.find(i => i.id ===id)
}

{{:~findSomething(~root, ~root.$pdf.pages[0].group).name}}

I understand it is a bit strange. This is how the chrome/puppeteer API works and we want to stay close to it and don't like to do its tweaks.
How it works...
You select display header/footer and it always adds the default header/footer until you fill something.

Maybe there could be another checkbox "display chrome default header/footer" but so far I would keep it as it is as everyone quickly finds out what to do.

For every request afterwards jsreport server throws the above error.
Then I have to restart the jsreport server every time when I am getting above error after then only I am able to generate documents.

This is the regression issue only present for http-server strategy.
It is fixed in jsreport 2.6.1

The right timeout to increase is this one. It isn't obvious, we will fix it in the upcoming release and provide general render timeout instead.

"templatingEngines": {
  "timeout": 60000,
  "strategy": "http-server"
}

My apologies. I've tested the unoconv with docx recipe and there was really a bug you mentioned.
It is now fixed in jsreport-unoconv@0.3.0. Please install it using

npm i jsreport-unoconv@0.3.0 --save

Would you be able to share your entities' export zip?