Trying to stringify an object to JSON, but not enough memory to fit the whole thing in memory

I don't understand what you're suggesting?

HISTORY object contains 8 typed 48 element arrays (representing data every 30 minutes), 4 Float32Arrays and 4 Uint16Arrays. The time data is not retained - I push onto one end and drop the oldest value every time I update it (by looping over the arrays since I can't do push() with a typed array). This works.

The problem is that I need to stringify the whole thing and send it as JSON to the webpage that will display it as a nice neat graph. However, I get out of memory when I do this - in the above, I've commented out all except RH, Temp, and Clear - which works, but then I don't get to have all the data I want.
I've tried breaking it all up into separate documents, but this doesn't work either - still runs out of memory, I think because it's not waiting until everything gets sent before stuffing more into the bufer.

It looks like the drain() method is made just for this kind of thing - but I don't know how to use it and there are no examples :-(