Sankey

Sankey :: # (opaque)

A Sankey flow diagram whose endpoints are checked at construction.

is_eq : _

Compare the encoded trace, including input order and all style settings.

new : Props -> Try(Sankey, [DuplicateNode(Str), MissingSource(Str), MissingTarget(Str), SelfLink(Str), InvalidLinkValue(F64), Infinity, NaN, NegativeInfinity])

Validate identities, endpoints and amounts before constructing a trace. Returns DuplicateNode(id) for repeated IDs, MissingSource(id) or MissingTarget(id) for absent endpoints, and SelfLink(id) when a link points back to the same node. Negative amounts return InvalidLinkValue(value); nonfinite amounts return NaN, Infinity, or NegativeInfinity. Rendering a successfully constructed trace performs no further graph validation.

expect {
    flow = Sankey.new({
        nodes: [{ id: "income", label: "Income" }, { id: "rent", label: "Rent" }],
        links: [{ source: "income", target: "rent", value: 1200 }],
    })?
    flow.to_json().contains("Income")
}

to_json_value : Sankey -> InternalJson

Internal composition hook used by Plume's renderers. Applications normally use Sankey.to_json for complete JSON text; this returns the package's safe internal value without accepting raw JSON.

to_json : Sankey -> Str

Serialize the trace as JSON.

Node

:= { id : Str, label : Str, color : Color ?? Color.rgb({ red: 31, green: 119, blue: 180 }), hover : [Default, Text(Str)] ?? Default }

One flow endpoint, with identity separate from its display text. id must be unique within the trace; links refer to this exact string. label is visible text and may be shared by multiple nodes. color defaults to Plotly blue. hover: Default preserves Plotly's hover information; Text(text) replaces it for this node. Hover text uses Plotly's supported markup rules.

Link

:= { source : Str, target : Str, value : F64, hover : [Default, Text(Str)] ?? Default }

One directed flow between distinct node IDs. source and target must match existing Sankey.Node IDs. value is finite and nonnegative; zero is accepted. hover: Default keeps Plotly's hover information, while Text(text) supplies an override. Cycles through distinct nodes are supported; self-links are rejected.

Props

:= { nodes : List(Node), links : List(Link), orientation : [Vertical, Horizontal] ?? Horizontal, name : Str ?? "" }

Configure a flow diagram. nodes defines stable output order; labels need not be unique. links resolves IDs against those nodes and retains input order. orientation defaults to Horizontal for left-to-right flow; use Vertical for top-to-bottom flow. name is the trace label. Both lists may be empty, but every supplied link needs valid endpoints.