Method fetchLedger

ts/src/xt.ts:3670–3721

* @method * @name xt#fetchLedger * @description fetch the history of changes, actions done by the user or operations that altered the balance of the user * @see https://doc.xt.com/#futures_usergetBalanceBill * @param {string} [code] unified currency code * @param {int} [sinc

(code: Str = undefined, since: Int = undefined, limit: Int = undefined, params = {})

     * @returns {object} a [ledger structure]{@link https://docs.ccxt.com/en/latest/manual.html#ledger-structure}
     */
    async fetchLedger (code: Str = undefined, since: Int = undefined, limit: Int = undefined, params = {}): Promise<LedgerEntry[]> {
        await this.loadMarkets ();
        const request = {};
        let currency: Currency = undefined;
        if (code !== undefined) {
            currency = this.currency (code);
        }
        if (since !== undefined) {
            request['startTime'] = since;
        }
        if (limit !== undefined) {
            request['limit'] = limit;
        }
        let type: Str = undefined;
        let subType: SubType = undefined;
        let response = undefined;
        [ type, params ] = this.handleMarketTypeAndParams ('fetchLedger', undefined, params);
        [ subType, params ] = this.handleSubTypeAndParams ('fetchLedger', undefined, params);
        if (subType === 'inverse') {
            response = await this.privateInverseGetFutureUserV1BalanceBills (this.extend (request, params));
        } else if ((subType === 'linear') || (type === 'swap') || (type === 'future')) {
            response = await this.privateLinearGetFutureUserV1BalanceBills (this.extend (request, params));
        } else {
            throw new NotSupported (this.id + ' fetchLedger() does not support spot transactions, only swap and future wallet transactions are supported');
        }
        //
        //     {
        //         "returnCode": 0,
        //         "msgInfo": "success",
        //         "error": null,
        //         "result": {
        //             "hasPrev": false,
        //             "hasNext": false,
        //             "items": [
        //                 {
        //                     "id": "207260567109387525",
        //                     "coin": "usdt",
        //                     "symbol": "btc_usdt",
        //                     "type": "FEE",
        //                     "amount": "-0.0213",
        //                     "side": "SUB",
        //                     "afterAmount": null,
        //                     "createdTime": 1679116769914
        //                 },
        //             ]
        //         }
        //     }
        //
        const data = this.safeValue (response, 'result', {});
        const ledger = this.safeValue (data, 'items', []);
        return this.parseLedger (ledger, currency, since, limit);
    }

    parseLedgerEntry (item, currency: Currency = undefined): LedgerEntry {
        //