feat: add collapseByDefault option to TableOfContents (closes #566)

quartz/plugins/transformers/toc.ts

@@ -8,12 +8,14 @@ export interface Options {
   maxDepth: 1 | 2 | 3 | 4 | 5 | 6
   minEntries: 1
   showByDefault: boolean
+  collapseByDefault: boolean
 }
 
 const defaultOptions: Options = {
   maxDepth: 3,
   minEntries: 1,
   showByDefault: true,
+  collapseByDefault: false,
 }
 
 interface TocEntry {
@@ -54,6 +56,7 @@ export const TableOfContents: QuartzTransformerPlugin<Partial<Options> | undefin
                   ...entry,
                   depth: entry.depth - highestDepth,
                 }))
+                file.data.collapseToc = opts.collapseByDefault
               }
             }
           }
@@ -66,5 +69,6 @@ export const TableOfContents: QuartzTransformerPlugin<Partial<Options> | undefin
 declare module "vfile" {
   interface DataMap {
     toc: TocEntry[]
+    collapseToc: boolean
   }
 }