Calculate Stochastic RSI like Tradingview does

[1amcord]

Because I know that these questions comes from time to time.
I'd like to share with you how I calculate the Stochastic RSI like Tradingview does:

import { RSI, SMMA, SMA } from 'trading-signals';
import { fetchOHLCVSince } from './ohlcv.js'
import Big from 'big.js';
import Debug from 'debug';
import { StochasticOscillator } from 'trading-signals';
import { NotEnoughDataError } from 'trading-signals';

const { debug } = Debug;
const logger = debug('StochRSI')




export async function getStochRSI(exchange, symbol) {

    const markets = await exchange.loadMarkets()
    const timeframe = '30m'

    const now = exchange.milliseconds()
    const startDate = 60 * 60 * 24 * 3 * 1000 // Three days back
    const since = now - startDate
    const candles_since = await fetchOHLCVSince(exchange, symbol, timeframe, since);

    const { stochRSIk, stochRSId } = await StochRsiCalc(candles_since.ohlcvs)

    logger(`Stoch RSI k: ${stochRSIk} Stoch RSI d: ${stochRSId}`);

    return { stochRSIk, stochRSId };
}

async function StochRsiCalc(mArray) {
    //Input: Candles from ohlcv.js as input.
    //30m timeframe. 3 Days back.


    //    [
    //        [
    //            1504541580000, // UTC timestamp in milliseconds, integer
    //            4235.4,        // (O)pen price, float
    //            4240.6,        // (H)ighest price, float
    //            4230.0,        // (L)owest price, float
    //            4230.7,        // (C)losing price, float
    //            37.72941911    // (V)olume (in terms of the base currency), float
    //        ],
    //        ...
    //    ]

    const rsiClosing = new RSI(14, SMMA);
    const smoothD = new SMA(3);
    const smoothK = new SMA(3);
    const stochOszi = new StochasticOscillator(14, 3, SMA);

    let sK = 0.00;
    let sD = 0.00;

    //Iterate over candles
    for (var index = 0; index < mArray.length; index++) {
        const closing = Big(mArray[index][4]);

        //Step 1: Calc closing RSI
        rsiClosing.update(closing);

        //Use rsiClosing as input for StochasticOszilator
        if (rsiClosing.isStable) {

            stochOszi.update({
                high: rsiClosing.getResult(),
                low: rsiClosing.getResult(),
                close: rsiClosing.getResult(),
            });
        }

        //calc k: stochOszis k - smoothed
        if (stochOszi.isStable) {
            let { k, d } = stochOszi.getResult();
            smoothK.update(k);
            if (smoothK.isStable) {
                //calc d: smoothed k - smoothed
                smoothD.update(smoothK.getResult());
            }
        }
    }
    if (stochOszi.isStable) {
        sK = smoothK.getResult().toFixed(2);
    } else {
        throw new Error('Not enough Data to calculate SMA K')
    }
    if (stochOszi.isStable) {
        sD = smoothD.getResult().toFixed(2);
    } else {
        throw new Error('Not enough Data to calculate SMA D')
    }

    return { stochRSIk: sK, stochRSId: sD };
}

[bennycode]

@1amcord thanks for sharing this with us. Would you like to contribute your code as a PR to this library? :)

[1amcord]

Hey @bennycode. I don't know if it fits somewhere into the library because it's only a code snipped.
But I can give it a try and rework if you think it would make sense.

[bennycode]

Are your calculations matching the results from here? https://tulipindicators.org/stochrsi

If yes, then it would be great to add StochasticRSI.ts to this directory: https://github.com/bennycode/trading-signals/tree/main/src/STOCH 😀