What is recommended practice for creating arrays of structured data?

As an update to this conversation, I had to make a minor change to the data buffer, changing it from ArrayBuffer to Uint8Array so that I could use buf.set(...) to push the older samples out. I presume that .set is going to be more efficient than anything I could have done programmatically.

So here are the relevant snippets from my working code:

var ELEMENT_SIZE = 10;  // 10 bytes per data structure (uint32, 3 x int16)
...
// define various setters and getters (could probably put this in a 'required' module
DataView.prototype.setInt16i = function(v) {
  this.setInt16(this.idx,v);
  this.idx+=2;
};
DataView.prototype.setUint32i = function(v) {
  this.setInt32(this.idx,v);
  this.idx+=4;
};
DataView.prototype.getInt16i = function() {
  var v = this.getInt16(this.idx);
  this.idx+=2;
  return v;
};
DataView.prototype.getUint32i = function() {
  var v = this.getInt32(this.idx);
  this.idx+=4;
  return v;
};
DataView.prototype.flush = function() {
  this.idx=0;
};

// buffer to store data samples
var buf = new Uint8Array(100*ELEMENT_SIZE);  // enough room for 100 samples
var d = new DataView(buf.buffer);
d.flush();
...
// A function to sample and store data into buffer
function log() {
  // is the buffer full?  If so, push it
  if (d.idx >= d.buffer.length-ELEMENT_SIZE) {
    // move all history values back by one element
    buf.set(new Uint8Array(buf.buffer,ELEMENT_SIZE));
    d.idx -= ELEMENT_SIZE;  
  }
  
  // sample the rest of the data and store it all in buffer
  d.setUint32i(Math.floor(Date.now()/1000)­);
  d.setInt16i(Math.floor(NRF.getBattery()*­1000));
  d.setInt16i(temps[0]);
  d.setInt16i(temps[1]);
  
}
...
// This is a utility function that will output our data
// in a form that can just be copy/pasted into a spreadsheet
function output() {
  clearInterval(timer);
  var saveIdx = d.idx;
  d.flush();
  while (d.idx < saveIdx) {
    var dt = d.getUint32i();
    var bat = d.getInt16i();
    var temp1 = d.getInt16i();
    var temp2 = d.getInt16i();
    var line = [dt,bat/1000,temp1/10,temp2/10].join(","­);
    console.log(line+"\n");
    i++;
  }
  d.idx = saveIdx;
  startSampling();
}

Note that the output() function might look a bit cumbersome, but that's mainly because I want to retain the current data set rather than output and flush the old stuff...

Thanks for everyone's help!
Tom