poller.js

function Poller(method) {
  if (typeof method !== "function") {
    throw new TypeError("Constructor must be passed a function!");
  }
  this.queryMethod = method;
  this.storage = null;
  this.interval = null;
}

Poller.prototype.queryThis = function() {
  return this.queryMethod();
};
Poller.prototype.queryAndStore = function() {
  this.storage = this.queryMethod();
  return this.storage;
};
Poller.prototype.start = function(timeInterval) {
  if (timeInterval <= 0) {
    throw new RangeError("time passed to start method must be physically possible");
  }
  this.interval = setInterval(this.queryMethod, timeInterval);
  return this.interval;
};
Poller.prototype.stop = function() {
  clearInterval(this.interval);
};
Poller.prototype.startAndStore = function(timeInterval) {
  if (timeInterval <= 0) {
    throw new RangeError("time passed to start method must be physically possible");
  }
  this.interval = setInterval(function() {
    this.storage = this.queryMethod();
  }, timeInterval);
  return this.interval;
};
Poller.prototype.retrieveStorage = function() {
  return this.storage;
};

//if method that needs to be called is async
//use this instead of Poller.prototype.startAndStore
//make that method have 1 argument that's a callback and calls it w/ the data to be stored as an argument 
Poller.prototype.startAsyncStore = function(timeInterval) {
  if (timeInterval < 0) {
    throw new RangeError("time passed to start method must be physically possible");
  }
  this.interval = setInterval(function() {
    this.queryMethod(function(data) {
      this.storage = data;
    });
  }, timeInterval);
  return this.interval;
};

module.exports = {
  Poller
};