all files / technicalindicators/lib/moving_averages/ WEMA.js

75.68% Statements 28/37
41.67% Branches 5/12
60% Functions 3/5
75% Lines 27/36
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63                    90× 42×   48×   90× 90×                                             90× 90× 51×    
"use strict"
//TODO; THis is copied from EMA for checking if WEMA works correctly, we need to refactor if this works good.
const SMA        = require('./SMA');
const nf = require('./../Utils/NumberFormatter');
 
let WEMA;
 
 
 
module.exports = WEMA = function(input) {
 
  var period = input.period
  var priceArray = input.values;
  var sma;
  this.format = input.format || nf;
 
  this.result = [];
 
  sma = new SMA({period : period, values :[], format : (v) => {return v}});
 
  this.generator = (function* (){
    var tick = yield;
    var prevMa,currentMa;
    while (true) {
      if(prevMa === undefined){
        currentMa = sma.nextValue(tick);
      }else {
        currentMa = ((prevMa * (period - 1)) + tick) / period;
      }
      prevMa = currentMa;
      tick = yield currentMa;
    }
  })();
 
  this.generator.next();
 
  priceArray.forEach((tick) => {
    var result = this.generator.next(tick);
    if(result.value){
      this.result.push(this.format(result.value));
    }
  });
};
 
WEMA.calculate = function(input) {
  if(input.reversedInput) {
    input.values.reverse();
  }
  let result = (new WEMA(input)).result;
  input.reversedInput ? result.reverse():undefined;
  return result;
};
 
WEMA.prototype.getResult = function () {
  return this.result;
};
 
WEMA.prototype.nextValue = function (price) {
  var nextResult = this.generator.next(price);
  if(nextResult.value)
    return this.format(nextResult.value);
};