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

Dereference reference columns into the drawn nodes they name (resolve(cols, { from, key? })).

Option	Type	Default	Description
cols	string[]		Required. Local columns holding references to resolve in place.
from	string		The selectAll(layerName) of a prior layer whose nodes the columns are matched against.
key	string		Explicit match field; defaults to the producing operator's 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.