Helper Functions (q)

The q namespace provides 12 utility functions available globally in onBar(). These are pure functions — they do not modify state.

Reference

Function	Signature	Description
`q.crossOver`	`(a: number[], b: number[]\|number, i: number) => boolean`	`a` crosses above `b` at bar `i`
`q.crossUnder`	`(a: number[], b: number[]\|number, i: number) => boolean`	`a` crosses below `b` at bar `i`
`q.highest`	`(series: number[], period: number, i: number) => number`	Highest value in lookback
`q.lowest`	`(series: number[], period: number, i: number) => number`	Lowest value in lookback
`q.sma`	`(series: number[], period: number, i: number) => number`	Simple moving average over lookback
`q.isNaN`	`(value: number) => boolean`	Check if indicator is not yet computed
`q.clamp`	`(value: number, min: number, max: number) => number`	Constrain value within range
`q.between`	`(value: number, min: number, max: number) => boolean`	Check if value is within range
`q.pctChange`	`(a: number, b: number) => number`	Percentage change from `b` to `a`
`q.sign`	`(value: number) => -1 \| 0 \| 1`	Sign of a number
`q.abs`	`(value: number) => number`	Absolute value
`q.round`	`(value: number, decimals: number) => number`	Round to N decimal places

Examples

function onBar(ctx, i) {
  const close = ctx.series.close;
  const ema = ctx.ind.ema;

  // Skip bars where indicator isn't ready
  if (q.isNaN(ema[i])) return;

  // Detect crossover
  if (q.crossOver(close, ema, i)) {
    ctx.order.market('ASSET', 1, { signal: 'buy' });
  }

  // Use a constant threshold
  if (q.crossUnder(ctx.ind.rsi, 30, i)) {
    ctx.order.market('ASSET', 1, { signal: 'rsi_oversold' });
  }

  // Donchian-style breakout using helpers
  const highest20 = q.highest(ctx.series.high, 20, i);
  if (close[i] > highest20) {
    ctx.order.market('ASSET', 1, { signal: 'breakout' });
  }

  // Inline SMA for volume filter
  const avgVol = q.sma(ctx.series.volume, 20, i);
  if (ctx.series.volume[i] < avgVol * 0.5) return; // Low volume, skip

  // Position sizing with clamp
  const rawSize = q.round(10000 / close[i], 4);
  const size = q.clamp(rawSize, 0.01, 5);
  
  // RSI neutral zone check
  if (q.between(ctx.ind.rsi[i], 40, 60)) {
    // Neutral — no strong signal
  }
}

Notes

q.crossOver and q.crossUnder accept either an array or a constant as the second argument
All lookback functions (highest, lowest, sma) return NaN if the lookback window extends before bar 0
q.pctChange(a, b) returns (a - b) / b as a decimal (0.05 = 5%)

Helper Functions (q)

Reference

Examples

Notes

Related