Add optional TOC inclusion feature

Jule Marcoueille · Jule Marcoueille · commit 7aa6aa9ff3f6 · 2021-01-13T00:05:38.000+01:00
diff --git a/src/options.ts b/src/options.ts
@@ -32,9 +32,9 @@ export interface Options {
   /**
    * The optional placeholder string to replace with the table of contents.
    *
-   * Defaults to "{{TOC}}";
+   * Defaults to `undefined`;
    */
-  placeholder?: string;
+  placeholder?: string | undefined;
 
   /**
    * HTML heading elements to include in the table of contents.
@@ -113,7 +113,7 @@ export class NormalizedOptions {
   public readonly position: InsertPosition;
   public readonly headings: HeadingTagName[];
   public readonly cssClasses: Required<CssClasses>;
-  public readonly placeholder?: string;
+  public readonly placeholder?: string | undefined;
   public readonly customizeTOC?: CustomizationHook;
   public readonly customizeTOCItem?: CustomizationHook;
 
@@ -125,7 +125,7 @@ export class NormalizedOptions {
 
     this.nav = options.nav === undefined ? true : Boolean(options.nav);
     this.position = options.position || "afterbegin";
-    this.placeholder = options.placeholder || "{{TOC}}";
+    this.placeholder = options.placeholder;
     this.headings = options.headings || ["h1", "h2", "h3", "h4", "h5", "h6"];
     this.cssClasses = {
       toc: cssClasses.toc === undefined ? "toc" : cssClasses.toc,
diff --git a/src/rehype-toc.ts b/src/rehype-toc.ts
@@ -21,8 +21,19 @@ export function toc(this: Processor, opts?: Options): Transformer {
       throw new Error("`root` is not a Root hast node.");
     }
 
-    // Find the <main> or <body> element
-    let [mainNode, mainParent] = findMainNode(root);
+    let mainNode: Element | undefined;
+    let mainParent: Parent | undefined;
+
+    if (options.placeholder) {
+      // Find the <target> element if option is given
+      [mainNode, mainParent] = findPlaceholderNode(root, options.placeholder);
+
+      if (!mainNode || !mainParent) { return root; }
+    }
+    else {
+      // Find the <main> or <body> element
+      [mainNode, mainParent] = findMainNode(root);
+    }
 
     // Find all heading elements
     let headings = findHeadings(mainNode, options);
@@ -33,16 +44,9 @@ export function toc(this: Processor, opts?: Options): Transformer {
     // Allow the user to customize the table of contents before we add it to the page
     let node = customizationHooks(tocNode, options);
 
-    // Find the <target> element is option is given
-    let target: Element | undefined;
-    let parent: Parent | undefined;
-    if (options.placeholder) {
-      [target, parent] = findPlaceholderNode(root, options.placeholder);
-    }
-
     if (node) {
       // Add the table of contents to the <main> element
-      insertTOC(node, target || mainNode, parent || mainParent, { ...options, replace: !!target && !!parent });
+      insertTOC(node, mainNode, mainParent, { ...options, replace: !!options.placeholder });
     }
 
     return root;
