Trade batcher

A busy trade feed may deliver many individual messages between screen updates. Sending every message through a separate native call adds work even when those trades could be processed together. The trade batcher collects them briefly and forwards them in one updateTrades call.

Create one batcher for each chart and feed, call add as trades arrive, and dispose it when the subscription ends. The default interval is 32 milliseconds. Batching keeps the individual trades so the native engine can still calculate their candle prices and volume.

createTradeBatcher(chartId: string, options?: TradeBatcherOptions): TradeBatcher returns the add, flush and dispose methods. Use flush when you need to send the pending batch before a controlled transition.

Property	Type / values	Default	Description
intervalMs	Integer from 1 to 2_147_483_647	32	Scheduled delay before forwarding queued trades.

Batcher method	Arguments	Returns	Description
add	TradeEvent	void	Validates and queues one non-decreasing trade.
flush	None	void	Immediately sends the queued batch.
dispose	None	void	Cancels the timer, drops queued trades, and permanently stops the batcher.

Lifecycle example

import { useEffect } from 'react';
import {
  createTradeBatcher,
  TradingCharts,
  TradingChartsView,
  type OhlcCandle,
  type TradeEvent,
} from 'react-native-trading-charts';

type Props = {
  chartId: string;
  history: readonly OhlcCandle[];
  // Your feed adapter returns its unsubscribe function.
  subscribe: (onTrade: (trade: TradeEvent) => void) => () => void;
};

export function StreamingChart({ chartId, history, subscribe }: Props) {
  useEffect(() => {
    TradingCharts.setHistory(chartId, history);
    const batcher = createTradeBatcher(chartId, { intervalMs: 32 });
    const unsubscribe = subscribe((trade) => batcher.add(trade));
    return () => {
      unsubscribe();
      batcher.dispose();
    };
  }, [chartId, history, subscribe]);

  return (
    <TradingChartsView
      style={{ height: 420 }}
      chartId={chartId}
      resolution={{ unit: 'minute' }}
    />
  );
}

Validation and teardown

A blank chartId or invalid interval throws TypeError during creation. add validates immediately: timestamps are safe non-negative integer milliseconds and non-decreasing across the entire batcher lifetime, price is finite, and optional size is finite and non-negative. Equal timestamps are allowed. Invalid trades throw TypeError; adding after disposal throws Error.

The timer starts with the first queued trade. The interval schedules delivery, but JavaScript scheduling can delay execution. flush sends queued trades and cancels the pending timer. dispose drops pending trades; call flush() before dispose() only when a controlled transition should deliver that final batch. Repeated dispose and flush after disposal are no-ops.