Strategy Development Guide

Strategies extend the Strategy class to add position tracking, order execution, and backtesting support.

Strategy vs Script

Feature	Script	Strategy
Base class	extends Script	extends Strategy
Position tracking	No	this.position.isLong, etc.
Order execution	No	this.strategy.entry(), etc.
Backtesting	No	Yes (via Backtest button)
Plotting	All plot types	All plot types
Built-in functions	All	All (inherits from Script)

Basic Structure

import { Script, Strategy, input, plot, plotShape, color } from '@chartlabs/script-sdk';

export default class MyStrategy extends Strategy {
  fastLen = input.number('Fast EMA', 9, { min: 1, max: 100 });
  slowLen = input.number('Slow EMA', 21, { min: 1, max: 200 });

  calculate() {
    const fast = this.ema('close', this.fastLen);
    const slow = this.ema('close', this.slowLen);

    plot('Fast', fast, { color: color.cyan, width: 2, overlay: true });
    plot('Slow', slow, { color: color.orange, width: 2, overlay: true });

    if (this.bar > 0) {
      const pf = this.getPlot('Fast', 1);
      const ps = this.getPlot('Slow', 1);

      if (this.crossOver(fast, slow, pf, ps)) {
        this.strategy.entry('Buy', 'long');
      }
      if (this.crossUnder(fast, slow, pf, ps)) {
        this.strategy.close('Exit');
      }
    }
  }
}

Position Object

Access current position state via this.position:

Property	Type	Description
isLong	boolean	Currently in a long position
isShort	boolean	Currently in a short position
isFlat	boolean	No open position
size	number	Position size (quantity)
entryPrice	number	Average entry price
entryBar	number	Bar index where position was opened

// Only enter if not already in a position
if (buyCondition && this.position.isFlat) {
  this.strategy.entry('Buy', 'long');
}

Order Methods

strategy.entry(signal, direction, options?)

Open a new position or add to an existing one.

this.strategy.entry('Buy Signal', 'long', { qty: 1 });
this.strategy.entry('Short Signal', 'short', { qty: 2 });

• If you're long and call entry('x', 'short'), the long position is closed first (reversal)
• signal is a label for the trade
• direction must be 'long' or 'short'

strategy.exit(signal, from?, options?)

Close or reduce an existing position.

this.strategy.exit('Take Profit', 'long');
this.strategy.exit('Stop Loss');  // exits any direction

strategy.close(comment?)

Close the entire position immediately.

this.strategy.close('End of day exit');

strategy.cancel(signal) / strategy.cancelAll()

Cancel pending orders (for future use).

Complete Strategy Examples

EMA Crossover Strategy

import { Script, Strategy, input, plot, plotShape, color } from '@chartlabs/script-sdk';

export default class EMACrossStrategy extends Strategy {
  fastLen = input.number('Fast', 9, { min: 1, max: 100 });
  slowLen = input.number('Slow', 21, { min: 1, max: 200 });

  calculate() {
    const fast = this.ema('close', this.fastLen);
    const slow = this.ema('close', this.slowLen);
    plot('Fast', fast, { color: color.cyan, width: 2, overlay: true });
    plot('Slow', slow, { color: color.orange, width: 2, overlay: true });

    if (this.bar > 0) {
      const pf = this.getPlot('Fast', 1);
      const ps = this.getPlot('Slow', 1);
      if (this.crossOver(fast, slow, pf, ps)) {
        this.strategy.entry('Buy', 'long');
        plotShape('Buy', true, { shape: 'triangleup', location: 'belowbar', color: color.green });
      }
      if (this.crossUnder(fast, slow, pf, ps)) {
        this.strategy.close('Sell');
        plotShape('Sell', true, { shape: 'triangledown', location: 'abovebar', color: color.red });
      }
    }
  }
}

RSI Mean Reversion

import { Script, Strategy, input, plot, plotShape, hline, color } from '@chartlabs/script-sdk';

export default class RSIMeanReversion extends Strategy {
  length = input.number('RSI Period', 14, { min: 2, max: 100 });
  oversold = input.number('Oversold', 30, { min: 0, max: 50 });
  overbought = input.number('Overbought', 70, { min: 50, max: 100 });

  calculate() {
    const rsi = this.rsi('close', this.length);
    plot('RSI', rsi, { color: color.purple, width: 2 });
    hline('OB', this.overbought, { color: color.red, style: 'dashed' });
    hline('OS', this.oversold, { color: color.green, style: 'dashed' });

    if (rsi < this.oversold && this.position.isFlat) {
      this.strategy.entry('RSI Buy', 'long');
      plotShape('Buy', true, { shape: 'triangleup', location: 'belowbar', color: color.green });
    }
    if (rsi > this.overbought && this.position.isLong) {
      this.strategy.close('RSI Sell');
      plotShape('Sell', true, { shape: 'triangledown', location: 'abovebar', color: color.red });
    }
  }
}

SuperTrend Trend Following

import { Script, Strategy, input, plotColor, plotShape, color } from '@chartlabs/script-sdk';

export default class SuperTrendStrategy extends Strategy {
  period = input.number('ATR Period', 10, { min: 1, max: 100 });
  factor = input.number('Factor', 3.0, { min: 0.5, max: 10, step: 0.5 });

  calculate() {
    const st = this.supertrend(this.period, this.factor);
    plotColor('ST', st.value, [color.green, color.red],
      st.direction === 1 ? 0 : 1, { width: 2 });

    // Track direction changes
    this.setState('dir', st.direction);
    const prevDir = this.bar > 0 ? this.getState('dir') : st.direction;

    if (st.direction === 1 && prevDir === -1) {
      this.strategy.entry('ST Buy', 'long');
      plotShape('Buy', true, { shape: 'triangleup', location: 'belowbar', color: color.green });
    }
    if (st.direction === -1 && prevDir === 1) {
      this.strategy.close('ST Sell');
      plotShape('Sell', true, { shape: 'triangledown', location: 'abovebar', color: color.red });
    }
  }
}

Backtesting

After writing a strategy:

1. Click Run to compile and execute
2. Click the Backtest button in the toolbar
3. Review results: trade count, win rate, profit factor, Sharpe ratio, equity curve

Tips

• Check position before entry: Use this.position.isFlat to avoid duplicate entries
• Use signal labels: They help identify trades in backtest results
• Add visual signals: Use plotShape() to mark entry/exit points on the chart
• Test on multiple instruments: Different markets may behave differently
• Keep it simple: Start with one entry condition and one exit condition, then add complexity