feature

Bull bar

Marks every bar that closes above its open. Payload carries bar range for later studies.

What it defines

A Collectable event bull_bar whenever close > open.

Key decisions

Piece	Why it matters
`kind: "flow"`	Enables emit / Collect (not an indicator).
`events.declare` + payload schema	Contract for Collect and studies.
Required `label` on `ctx.emit`	Events without labels are dropped at runtime.
Early `return` on bear bars	Keep `onBar` cheap when the setup is false.

Full script

meta({
  name: "Bull bar",
  kind: "flow",
  slug: "bull-bar",
  shortName: "BullBar",
});

events.declare({
  id: "bull_bar",
  intent: "Mark closes above open",
  payload: {
    range: { type: "number", description: "High minus low" },
    close: { type: "number", description: "Close price" },
  },
  paint: "pin",
});

outputs.declare({
  id: "close_line",
  kind: "line",
  name: "Close",
  color: "#64b5f6",
});

export function onBar(ctx) {
  ctx.plot("close_line", ctx.close);

  if (ctx.close <= ctx.open) return;

  const range = ctx.high - ctx.low;
  ctx.emit(
    "bull_bar",
    { range, close: ctx.close },
    {
      label: `Bull · R=${range.toFixed(2)}`,
      subtitle: `close ${ctx.close.toFixed(2)}`,
      price: ctx.close,
      timeStart: ctx.time,
    }
  );
}

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