@lacspace/indicators

Streaming technical indicators for live price feeds — push one tick, get the new value in O(1).

Most JS indicator libs recompute the entire array on every new candle. This one updates incrementally — feed a single live LTP tick and the indicator advances in O(1). Built for real-time charts, screeners and algo bots.

• 📈 RSI, MACD, SMA, EMA, WMA, Bollinger, ATR, VWAP, Stochastic, Supertrend, ADX
• ⚡ Incremental next(tick) API — perfect for websocket / LTP streams
• 🧮 Batch helpers too — run over a historical array in one call
• ✂️ crossedAbove / crossedBelow for signal logic
• 🌍 Isomorphic (browser + Node) · 📦 ESM + CJS · 🧩 zero dependencies · fully typed

Install

npm install @lacspace/indicators      # or pnpm add / yarn add / bun add

Streaming — the whole point

import { RSI, MACD } from "@lacspace/indicators";

const rsi = new RSI(14);
const macd = new MACD(12, 26, 9);

// wire straight into your tick feed
socket.on("ltp", (price) => {
  const r = rsi.next(price);       // O(1) — no array recompute
  const m = macd.next(price);
  if (r !== null && r > 70) console.log("overbought", r.toFixed(1));
  if (m) console.log("histogram", m.histogram.toFixed(2));
});

Every indicator returns null during its warm-up window, then a number (or a struct), and also exposes .value.

Batch over history

import { rsi, ema, bollinger, supertrend } from "@lacspace/indicators";

const closes = candles.map((c) => c.close);

rsi(closes, 14);          // (number | null)[]
ema(closes, 20);          // (number | null)[]
bollinger(closes, 20, 2); // ({ middle, upper, lower, bandwidth } | null)[]

// range-based indicators take OHLC bars
supertrend(candles, 10, 3); // ({ value, direction: 1 | -1 } | null)[]

Signals with crossovers

import { ema, crossedAbove } from "@lacspace/indicators";

const fast = ema(closes, 9);
const slow = ema(closes, 21);

for (let i = 1; i < closes.length; i++) {
  if (fast[i - 1] == null || slow[i - 1] == null) continue;
  const golden = crossedAbove(
    { a: fast[i - 1]!, b: slow[i - 1]! },
    { a: fast[i]!, b: slow[i]! },
  );
  if (golden) console.log("EMA golden cross at bar", i);
}

Indicators

| Class / fn | Input | Output | | --- | --- | --- | | SMA EMA WMA | price | number | | RSI | price | 0–100 | | MACD | price | { macd, signal, histogram } | | BollingerBands | price | { middle, upper, lower, bandwidth } | | ATR | HLC bar | number | | VWAP | H/L/C/volume bar | number | | Stochastic | HLC bar | { k, d } | | Supertrend | HLC bar | { value, direction } | | ADX | HLC bar | { adx, plusDI, minusDI } |

Batch equivalents: sma ema wma rsi macd bollinger atr supertrend adx.

The Lacspace StockKit

| Package | For | | --- | --- | | @lacspace/indicators | Technical indicators (this package) | | @lacspace/market | P&L, XIRR, brokerage & charges | | @lacspace/market-clock | Is the market open? holidays | | @lacspace/paper-trade | Headless paper-trading engine |

New in 1.1 — candle aggregation & pattern detection

import { CandleAggregator, detectPatterns } from "@lacspace/indicators";

// Turn a live LTP/tick feed into fixed-interval OHLC candles
const agg = new CandleAggregator(60_000); // 1-minute
onTick(({ time, price, volume }) => {
  const candle = agg.add({ time, price, volume });
  if (candle) store.push(candle); // completed candle on each rollover
});

// Spot candlestick patterns across a series
detectPatterns(candles);
// → [{ index: 42, pattern: "bullishEngulfing", bullish: true }, …]
// doji · hammer · shootingStar · marubozu · bullish/bearish engulfing · harami

Licensing

This package is free under the Lacspace Free Licence — MIT-equivalent freedoms. Use it in personal and commercial projects at no cost; just keep the notice.

Not every Lacspace package is free. We also offer Commercial (paid), Client-specific, and Private (proprietary) packages under separate terms. See the full Lacspace Licence Centre.

Part of the Lacspace ecosystem — 35 zero-dependency, isomorphic TypeScript packages.

All packages ↗ · npm org ↗ · Licence Centre ↗ · GitHub ↗