resolve

Dereference reference columns into the drawn nodes they name. For each row, resolve matches the listed columns' values against the keyed nodes of from (a selectAll(...) of a prior layer) and replaces each value in place with the matching node ref — a many-to-one join that preserves the row grain (no fan-out). It's the join that turns an edge or label table into something the chart can draw.

Pair it with .layer(table) to drive a tier from a second table, and with line({ from, to }) (node-link edges) or a composing function-mark (labels).

Node-link edges

const nodes = [
  { id: "a", grp: 0 },
  { id: "b", grp: 1 },
  { id: "c", grp: 1 },
  { id: "d", grp: 2 },
];
const edges = [
  { source: "a", target: "b" },
  { source: "a", target: "c" },
  { source: "b", target: "d" },
  { source: "c", target: "d" },
];

gf.chart(nodes)
  .flow(gf.scatter({ by: "id", x: "grp", y: "id" }))
  .mark(gf.circle({ r: 14, fill: "#4e79a7" }).name("nodes"))
  .layer(
    gf
      .chart(edges)
      .flow(gf.resolve(["source", "target"], { from: gf.selectAll("nodes") }))
      .mark(gf.line({ from: "source", to: "target", stroke: "#888" }))
  )
  .render(root, { w: 360, h: 360 });

Signature

resolve(cols, { from, key? });

Parameters

Parameter	Type	Description
cols	string[]	The columns whose values are references to resolve in place.
from	GoFishRef	A selectAll(layerName) of the layer whose nodes the columns are matched against.
key	string	Optional. The field on the from nodes to match against. Defaults to the field those nodes were grouped by (e.g. scatter({ by })).

Returns an Operator for use inside .flow().

Semantics

• Many-to-one — each reference resolves to exactly one node (the match field must be a key); the row grain is preserved, no rows are added.
• In place — the matched columns are replaced by node refs, so a downstream mark reads them directly (line({ from: "source", to: "target" })).
• Default key — when key is omitted, the match field is the one the from nodes were grouped by (scatter({ by: "id" }) ⇒ match on id). If those nodes were grouped by a function (no field name), pass an explicit key.
• Errors — a reference with no matching node throws, naming the column and value, rather than silently dropping the row.

resolve vs. derive

derive runs an opaque row transform; resolve is the specific, named case of joining reference columns against a drawn layer and replacing them with refs that read each node's post-layout position.