Res.json is blocking my node/express server

Question

Res.json is blocking my node/express server

I have a 100mb object that I try to return with a GET request:

function doWork(req,res) {

  // creates a big object on a child process, then returns this big object

  res.json(bigObject); // <--- problem line
}
app.get('/dowork', doWork);

Even though I am creating this big object on a child process I need the main process to return it (b/c the child process doesn't have the res stream). I'm wondering what's the proper way to do this? Right now converting this big object to json is horking my server for a while. No-one can connect while it is doing this.

javascript
node.js
express

Answer 1

Don't return it as an object from the child process. Instead, call JSON.stringify in there already, and stream it back to your main process. You can then hook this output stream of the child process to write to the res by using .pipe().