[PERFORMANCE] Provision indicator class with pre-computed values

[ColCh]

As I see, SMA (for example) starts with zero values

technicalindicators/lib/moving_averages/SMA.js

Line 24 in 7740f17

list.push(0);

technicalindicators/lib/moving_averages/SMA.js

Line 21 in 7740f17

var counter = 1;

technicalindicators/lib/moving_averages/SMA.js

Line 41 in 7740f17

this.result = [];

and then calculates price for passed values, or calculates next generator value

BUT I save calculated values into DB, and there is already calculated values for indicators

So, providing already calculated values from DB may greatly increase performance for calculation.

For now, it's required to calculate values for every indicator from scratch (e.g. on app startup), even if there is values retrieved from DB

e.g.

// startup code
const pastSMAValues = await mySMADBValues.select(); // [0, 0, 0, 1, 1.1, 1.2, 1.1]
const mySMA = new SMA({ pastValues: pastSMAValues });

// runtime code
// new tick retrieved from stream api 
cont newTick = { /* OHLC tick */ };
mySMA.nextValue(newTick); // 1.15 -> new SMA value for new tick based on passed pre-calculated SMA values