Compare action

Use this action with change({ id: 'Compare', context }).

Context

• id?: Get | Update (Update is assumed if omitted)
• plots: array of comparison plots
  • type: Symbol | Expression | Seasonal
  • uid: optional plot uid
  • symbol when type is Symbol
  • expression when type is Expression
  • seasonal when type is Seasonal
  • oppositeScale: true | false (leftScale is still accepted but deprecated)
  • curves: optional curve overrides
• symbols: deprecated compatibility alias for symbol-only compare list
• alignOnExpirations: true | false

Behavior

Configures comparison plots against the main plot.

• Supports symbol, expression, and seasonal comparison plots.
• Existing comparison plots are replaced by the incoming plots list.
• If a compare item supplies uid, it must be unique across all plots currently on the chart, regardless of plot type.
• Duplicate caller-supplied uid values within the same compare request are rejected.
• The package exports generateUid() if you want to pre-generate compare plot ids in the host app.
• By default, comparison plots share the main axis.
• oppositeScale: true puts a plot on the secondary/opposite axis.
• If curves is omitted, comparison plots render as lines with automatic colors.
• Curve values are merged with defaults, so partial overrides are fine.
• alignOnExpirations: true overlays eligible non-seasonal plots (mainly futures) as if they traded in the same year; the tooltip still shows actual trade dates.
• Seasonal comparison plots align internally, so alignOnExpirations does not control seasonal alignment.

Get returns the same top-level shape (plots, alignOnExpirations). Returned plots include canonical oppositeScale plus deprecated leftScale as a compatibility alias.

Example:

chart.change({
    id: "Compare",
    context: {
        plots: [
            { type: "Symbol", symbol: "AAPL" },
            { type: "Seasonal", seasonal: "CLM24", oppositeScale: true },
        ],
        alignOnExpirations: true,
    },
});