Add maxDepth option to specify which levels are included

index.js

@@ -124,9 +124,10 @@ function isClosingHeading(node, depth) {
  * @param {Node} root
  * @param {RegExp} expression
  * @param {function(string): string} library
+ * @param {number} maxDepth
  * @return {Object}
  */
-function search(root, expression, library) {
+function search(root, expression, library, maxDepth) {
     var index = -1;
     var length = root.children.length;
     var depth = null;
@@ -164,7 +165,7 @@ function search(root, expression, library) {
             }
         }
 
-        if (!lookingForToc && value) {
+        if (!lookingForToc && value && child.depth <= maxDepth) {
             map.push({
                 'depth': child.depth,
                 'value': value
@@ -464,6 +465,7 @@ function attacher(mdast, options) {
     var library = settings.library || DEFAULT_LIBRARY;
     var isNPM = library === NPM;
     var isGitHub = library === GITHUB;
+    var depth = settings.maxDepth || 6;
 
     if (isNPM || isGitHub) {
         library = SLUGG;
@@ -486,7 +488,7 @@ function attacher(mdast, options) {
      * @param {Node} node
      */
     function transformer(node) {
-        var result = search(node, heading, library);
+        var result = search(node, heading, library, depth);
 
         if (result.index === null || !result.map.length) {
             return;

mdast-toc.js

@@ -126,9 +126,10 @@ function isClosingHeading(node, depth) {
  * @param {Node} root
  * @param {RegExp} expression
  * @param {function(string): string} library
+ * @param {number} maxDepth
  * @return {Object}
  */
-function search(root, expression, library) {
+function search(root, expression, library, maxDepth) {
     var index = -1;
     var length = root.children.length;
     var depth = null;
@@ -166,7 +167,7 @@ function search(root, expression, library) {
             }
         }
 
-        if (!lookingForToc && value) {
+        if (!lookingForToc && value && child.depth <= maxDepth) {
             map.push({
                 'depth': child.depth,
                 'value': value
@@ -466,6 +467,7 @@ function attacher(mdast, options) {
     var library = settings.library || DEFAULT_LIBRARY;
     var isNPM = library === NPM;
     var isGitHub = library === GITHUB;
+    var depth = settings.maxDepth || 6;
 
     if (isNPM || isGitHub) {
         library = SLUGG;
@@ -488,7 +490,7 @@ function attacher(mdast, options) {
      * @param {Node} node
      */
     function transformer(node) {
-        var result = search(node, heading, library);
+        var result = search(node, heading, library, depth);
 
         if (result.index === null || !result.map.length) {
             return;

readme.md

@@ -125,9 +125,14 @@ Adds a [Table of Contents](#table-of-contents) to a Markdown document.
             — Library to use.
 
     *   `heading` (`string?`, default: `"toc|table[ -]of[ -]contents?"`)
-        — heading to look for, wrapped in
+        — Heading to look for, wrapped in
         `new RegExp('^(' + value + ')$', 'i');`.
 
+    *   `maxDepth` (`number?`, default: `6`)
+        — Maximum heading depth to include in the table of contents,
+        This is inclusive, thus, when set to `3`, level three headings,
+        are included (those with three hashes, `###`).
+
 ## License
 
 [MIT](LICENSE) © [Titus Wormer](http://wooorm.com)

test/fixtures/maximum-depth-1/config.json

@@ -0,0 +1,3 @@
+{
+  "maxDepth": 1
+}

test/fixtures/maximum-depth-1/input.md

@@ -0,0 +1,15 @@
+# Normal
+
+# Table of Contents
+
+# Alpha
+
+## Bravo
+
+### Charlie
+
+#### Delta
+
+##### Echo
+
+###### Foxtrot

test/fixtures/maximum-depth-1/output.md

@@ -0,0 +1,17 @@
+# Normal
+
+# Table of Contents
+
+-   [Alpha](#alpha)
+
+# Alpha
+
+## Bravo
+
+### Charlie
+
+#### Delta
+
+##### Echo
+
+###### Foxtrot

test/fixtures/maximum-depth-3/config.json

@@ -0,0 +1,3 @@
+{
+  "maxDepth": 3
+}

test/fixtures/maximum-depth-3/input.md

@@ -0,0 +1,15 @@
+# Normal
+
+# Table of Contents
+
+# Alpha
+
+## Bravo
+
+### Charlie
+
+#### Delta
+
+##### Echo
+
+###### Foxtrot

test/fixtures/maximum-depth-3/output.md

@@ -0,0 +1,21 @@
+# Normal
+
+# Table of Contents
+
+-   [Alpha](#alpha)
+
+    -   [Bravo](#bravo)
+
+        -   [Charlie](#charlie)
+
+# Alpha
+
+## Bravo
+
+### Charlie
+
+#### Delta
+
+##### Echo
+
+###### Foxtrot

test/fixtures/maximum-depth-6/config.json

@@ -0,0 +1,3 @@
+{
+  "maxDepth": 6
+}

test/fixtures/maximum-depth-6/input.md

@@ -0,0 +1,15 @@
+# Normal
+
+# Table of Contents
+
+# Alpha
+
+## Bravo
+
+### Charlie
+
+#### Delta
+
+##### Echo
+
+###### Foxtrot

test/fixtures/maximum-depth-6/output.md

@@ -0,0 +1,27 @@
+# Normal
+
+# Table of Contents
+
+-   [Alpha](#alpha)
+
+    -   [Bravo](#bravo)
+
+        -   [Charlie](#charlie)
+
+            -   [Delta](#delta)
+
+                -   [Echo](#echo)
+
+                    -   [Foxtrot](#foxtrot)
+
+# Alpha
+
+## Bravo
+
+### Charlie
+
+#### Delta
+
+##### Echo
+
+###### Foxtrot