subprocess output truncated

var child = require('child_process');

function runScript() {
  console.log('runScript');
  var args = [__filename, 'spew'];
  child.execFile(
    'node',
    args,
    function(exitCode, stdout, stderr) {
      console.log('execFile:done');
      if (exitCode) {
        return console.error('error!!! stderr: '+stderr);
      }
      console.log('parsing JSON');
      json = JSON.parse(stdout);
      console.log('done. yaay!');
    }
  );
}

function spew() {
  var str = ('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'
    +'0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789');
  var res = {};
  for (var i = 0; i < 100; i++) {
    res[i] = i+' '+str;
  };
  console.log(JSON.stringify(res));
}

if (!module.parent) {
  var cmdline = process.argv.join(' ');
  if (cmdline.indexOf('spew') >= 0) {
    spew();
    process.exit(0); // comment this out to have output succeed.
    return;
  }
  console.log('main:',cmdline)
  runScript();
}