Method getDepthCache

src/node-binance-api.ts:3517–3520

* Gets depth cache for given symbol * @param {string} symbol - the symbol to fetch * @return {object} - the depth cache object

(symbol: string)

     * @return {object} - the depth cache object
     */
    getDepthCache(symbol: string) {
        if (typeof this.depthCache[symbol] === 'undefined') return { bids: {}, asks: {}};
        return this.depthCache[symbol];
    }

    /**
     * Calculate Buy/Sell volume from DepthCache