Plot basics

plot(name, value, opts?) // returns a handle { id, name }

// Step 1: top-level declaration - register the series and set visual options
plot("MA", null, { color: "#22c55eFF", linewidth: 2 });

// Step 2: inside onBar - write the value at the current bar
onBar(() => {
  plot("MA", ta.sma(ctx.close, 20));
});

// Single-call form (only useful for constant horizontal lines - prefer hline for that)
plot("Zero", 0, { color: "#6b7280FF" });

const upperPlot = plot("Upper", null, { color: "#22c55eFF" });
const lowerPlot = plot("Lower", null, { color: "#ef4444FF" });
fill(upperPlot, lowerPlot, { color: "#22c55e20" });

onBar(() => {
  const rsi = ta.rsi(ctx.close, 14);
  // Only plot when RSI is in overbought/oversold territory
  plot("Signal", rsi > 70 || rsi < 30 ? rsi : NaN);
});