Simple Javascript Circular Buffer

SimpleCircularBuffer.js

/** one way of doing it **/
var CircularBuffer = exports.CircularBuffer = function(size) {
  this.pos = 0
  this._buf = []
  this.size = size
}

CircularBuffer.prototype.get = function(i) {
  if (i == undefined) i = 0;
  if (i >= this.size) return undefined;
  if (i >= this._buf.length) return undefined;
  return this._buf[(this.pos - i - 1) % this.size]
}

CircularBuffer.prototype.push = function(o) {
  this._buf[this.pos % this.size] = o
  this.pos++
  return o
}


/** another way of doing it **/
var CircularBuffer = function(size) {
  this._buf = new Array(size); //= new Array(size);
    this.pos = 0;
}

CircularBuffer.prototype.get = function(i) {
	if (i == undefined) i = 0;
	if (i > this._buf.length) return null;
    return this._buf[i % this._buf.length];
};

CircularBuffer.prototype.push= function(o) {
    this._buf[this.pos % this._buf.length] = o;
    this.pos++;
};

CircularBuffer.prototype.toString = function() {
    return '[object CircularBuffer('+this._buf.length+') length '+this.pos+']';
};