Function area

area(
    topline: readonly (readonly [number, number])[],
    y0: number | readonly (readonly [number, number])[],
    config?: LineConfig,
): string | null
Generates a closed SVG path string for a filled area.

D3 parity: d3-shape/src/area.js — topline is drawn forward with the chosen curve, baseline is appended in reverse as straight segments, then closed.
Parameters
- topline: readonly (readonly [number, number])[]
  [x, y1] points — the curved upper boundary
- y0: number | readonly (readonly [number, number])[]
  Constant baseline y, or per-point [x, y0] array (straight baseline)
- config: LineConfig = {}
Returns string | null
- Defined in shape/area.ts:21