Pass large array to node child process

I have complex CPU intensive work I want to do on a large array. Ideally, I'd like to pass this to the child process.

var spawn = require('child_process').spawn;

// dataAsNumbers is a large 2D array
var child = spawn(process.execPath, ['/child_process_scripts/getStatistics', dataAsNumbers]);

child.stdout.on('data', function(data){
  console.log('from child: ', data.toString());
});

But when I do, node gives the error:

spawn E2BIG

I came across this article

So piping the data to the child process seems to be the way to go. My code is now:

var spawn = require('child_process').spawn;

console.log('creating child........................');

var options = { stdio: [null, null, null, 'pipe'] };
var args = [ '/getStatistics' ];
var child = spawn(process.execPath, args, options);

var pipe = child.stdio[3];

pipe.write(Buffer('awesome'));

child.stdout.on('data', function(data){
  console.log('from child: ', data.toString());
});

And then in getStatistics.js:

console.log('im inside child');

process.stdin.on('data', function(data) {
  console.log('data is ', data);
  process.exit(0);
});

However the callback in process.stdin.on isn't reached. How can I receive a stream in my child script?

EDIT

I had to abandon the buffer approach. Now I'm sending the array as a message:

var cp = require('child_process');
var child = cp.fork('/getStatistics.js');

child.send({ 
  dataAsNumbers: dataAsNumbers
});

But this only works when the length of dataAsNumbers is below about 20,000, otherwise it times out.