@ldrick/trade-indicators
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Trade Indicators
21 lines (20 loc) • 1.32 kB
JavaScript
import { apply as AP, either as E, function as F, readonlyNonEmptyArray as RNEA } from 'fp-ts';
import * as array from '../utils/array.js';
import * as number_ from '../utils/number.js';
import { emaC } from './ema.js';
const calculate = (one, two, three, period) => F.pipe(three, RNEA.mapWithIndex((index, value) => one[index + 2 * (period - 1)]
.mul(3)
.sub(two[index + period - 1].mul(3))
.add(value)
.toNumber()));
/**
* The Triple Exponential Moving Average (TEMA) uses three Exponential Moving Average (EMA)
* to reduce noise and still get close to latest prices.
* It can be used to identify support and resistance levels.
* Also prices above the TEMA can indicate uptrends, prices below can indicate downtrends.
* @public
*/
export const tema = (values, period = 20) => F.pipe(AP.sequenceS(E.Applicative)({
periodV: number_.validatePositiveInteger(period),
valuesV: array.validateRequiredSize(3 * period - 2)(values),
}), E.bind('valuesB', ({ valuesV }) => array.toBig(valuesV)), E.bind('emaOne', ({ periodV, valuesB }) => emaC(valuesB, periodV)), E.bind('emaTwo', ({ emaOne, periodV }) => emaC(emaOne, periodV)), E.bind('emaThree', ({ emaTwo, periodV }) => emaC(emaTwo, periodV)), E.map(({ emaOne, emaThree, emaTwo, periodV }) => calculate(emaOne, emaTwo, emaThree, periodV)));