stack

Like spread but with zero spacing — items stack edge-to-edge. Used for stacked bar charts.

gf.Chart(seafood)
  .flow(
    gf.spread("lake", { dir: "x" }),
    gf.stack("species", { dir: "y" })
  )
  .mark(gf.rect({ h: "count", fill: "species" }))
  .render(root, { w: 400, h: 250, axes: true });

Signature

stack(field, { dir, alignment = "start", w?, h? })

Parameters

Option	Type	Description
field	string	Field to group by before stacking
dir	"x" | "y"	Required. Stack direction
alignment	"start" | "middle" | "end"	Alignment within each slot
w	number | string	Width or field
h	number | string	Height or field

Example

// Stacked bar chart grouped by "site", stacked by "variety"
.flow(
  spread("variety", { dir: "x" }),
  stack("site", { dir: "y" })
)