text: // required indicators
  var SMMA = require('./SMMA.js');
  
  var Indicator = function (settings) {
    this.input = 'candle';
    this.lastClose = null;
    this.weight = settings.interval;
    this.avgU = new SMMA(this.weight);
    this.avgD = new SMMA(this.weight);
    this.u = 0;
    this.d = 0;
    this.rs = 0;
    this.result = 0;
    this.age = 0;
  }
  
  Indicator.prototype.update = function (candle) {
    var currentClose = candle.close;
  
    if (this.lastClose === null) {
      // Set initial price to prevent invalid change calculation
      this.lastClose = currentClose;
  
      // Do not calculate RSI for this reason - there's no change!
      this.age++;
      return;
    }
  
    if (currentClose > this.lastClose) {
      this.u = currentClose - this.lastClose;
      this.d = 0;
    } else {
      this.u = 0;
      this.d = this.lastClose - currentClose;
    }
  
    this.avgU.update(this.u);
    this.avgD.update(this.d);
  
    this.rs = this.avgU.result / this.avgD.result;
    this.result = 100 - (100 / (1 + this.rs));
  
    if (this.avgD.result === 0 && this.avgU.result !== 0) {
      this.result = 100;
    } else if (this.avgD.result === 0) {
      this.result = 0;
    }
  
    this.lastClose = currentClose;
    this.age++;
  }
  
  module.exports = Indicator;
  