add data-compartment attribute to svg output

src/GraphicsSvg.ts

@@ -102,7 +102,7 @@ export function GraphicsSvg(document?: HTMLDocument): ISvgGraphics {
       return this.parent
     }
     serialize(): string {
-      const data = getDefined(this.group(), (e) => e.data) ?? {}
+      const data = getAncestorData(this.group()) ?? {}
       const attrs = toAttrString({ ...this.attr, ...data })
       const content = this.children.map((o) => o.serialize()).join('\n')
       if (this.text && this.children.length === 0)
@@ -116,6 +116,11 @@ export function GraphicsSvg(document?: HTMLDocument): ISvgGraphics {
     }
   }
 
+  function getAncestorData(group: GroupElement | undefined): Record<string, string> | undefined {
+    if (!group) return syntheticRoot.data
+    return { ...getAncestorData(group.parent), ...group.data }
+  }
+
   function getDefined<T>(
     group: GroupElement | undefined,
     getter: (e: GroupElement) => T | undefined
@@ -129,7 +134,7 @@ export function GraphicsSvg(document?: HTMLDocument): ISvgGraphics {
       super('g', {}, parent)
     }
     elideEmpty = true
-    data: Record<string, string>
+    data: Record<string, string> | undefined
     group() {
       return this
     }

src/renderer.ts

@@ -58,6 +58,7 @@ export function render(graphics: Graphics, config: Config, compartment: Layouted
 
     g.save()
     g.setData('name', node.id)
+    g.setData('compartment', undefined)
 
     g.save()
     g.fillStyle(style.fill || config.fill[level] || last(config.fill))
@@ -73,9 +74,11 @@ export function render(graphics: Graphics, config: Config, compartment: Layouted
     }
     g.restore()
 
+    let partIndex = 0
     for (let part of node.parts) {
       const textStyle = part === node.parts[0] ? style.title : style.body
       g.save()
+      g.setData('compartment', String(partIndex))
       g.translate(x + part.x!, y + part.y!)
       g.setFont(
         config.font,
@@ -84,6 +87,7 @@ export function render(graphics: Graphics, config: Config, compartment: Layouted
         textStyle.italic ? 'italic' : 'normal'
       )
       renderCompartment(part, style.stroke, textStyle, level + 1)
+      partIndex++
       g.restore()
     }