node.js talib calculate simple moving average differs from binance and tradingview

I try to calculate the sma for the BTC/USDT pair with nodejs. Therefor I installed the talib module and created a socket to the binance markter ticker.

const WebSocketBinance_BTCUSDT = new WebSocket('wss://stream.binance.com:9443/ws/btcusdt@ticker');

let BTCUSDT = new Coin('Bitcoin in US-Dollar Tether');
WebSocketBinance_BTCUSDT.on('message', function incoming(data) {
        CoinMarket.BTCUSDT.update(JSON.parse(data));
});

So far everything works as expected. The Coin-Class looks like:

class Coin {
    constructor(bezeichnung) {
        this.name = bezeichnung;
        this.price = new Array(); 
    }
 
    get current() {
        return Number(this.price[this.price.length -1] ).toFixed(4)     
    }
    
    update(dataset) {
        this.price.push(Number(dataset.a).toFixed(4));  
    }
    
    ma(width){
        if (this.price.length < width) return;
        let val = 0; 
        for (let i = 1; i <= width; i++) {
            val += Number(this.price[this.price.length - i]) ; 
        }   
        return Number(val/(width)).toFixed(4);
    }
    
    
}

module.exports = {
    Coin
}

My problem is, that if I call ma(20) the value differs from that shown on Binance or Tradingview. Also TALib calculates a wrong Baseband for Bollinger Bands. I think this means that I use a wrong dataset to calculate a correct intraday moving average. But what values should I use ?

Best regards