Add strict to tsconfig.json

lib/contents.js

@@ -9,7 +9,7 @@
  * @typedef ContentsOptions
  * @property {boolean} [tight=false] Whether to compile list-items tightly.
  * @property {boolean} [ordered=false] Whether to compile list-items as an ordered list, otherwise they are unordered.
- * @property {string} [prefix=null] Add a prefix to links to headings in the table of contents. Useful for example when later going from mdast to hast and sanitizing with `hast-util-sanitize`.
+ * @property {string|null} [prefix=null] Add a prefix to links to headings in the table of contents. Useful for example when later going from mdast to hast and sanitizing with `hast-util-sanitize`.
  */
 
 import extend from 'extend'
@@ -97,7 +97,7 @@ function insert(entry, parent, settings) {
     entry.depth--
     insert(
       entry,
-      // @ts-ignore It’s a `list`, we just checked.
+      // @ts-expect-error It’s a `list`, we just checked.
       parent.children[parent.children.length - 1],
       settings
     )
@@ -157,20 +157,15 @@ function one(node) {
     node.type === 'footnote' ||
     node.type === 'footnoteReference'
   ) {
-    // @ts-ignore Looks like a parent.
+    // @ts-expect-error Looks like a parent.
     return all(node.children)
   }
 
-  let copy = extend({}, node)
-  if ('children' in copy) delete copy.children
-  delete copy.position
-
-  copy = extend(true, {}, copy)
-
   if ('children' in node) {
-    // @ts-ignore Looks like a parent.
-    copy.children = all(node.children)
+    const {children, position, ...copy} = node
+    return Object.assign(extend(true, {}, copy), {children: all(node.children)})
   }
 
-  return copy
+  const {position, ...copy} = node
+  return extend(true, {}, copy)
 }

lib/index.js

@@ -9,9 +9,9 @@
  * @property {string} [heading] Heading to look for, wrapped in `new RegExp('^(' + value + ')$', 'i')`.
  *
  * @typedef Result
- * @property {number} index
- * @property {number} endIndex
- * @property {List} map
+ * @property {number|null} index
+ * @property {number|null} endIndex
+ * @property {List|null} map
  */
 
 import {search} from './search.js'

lib/search.js

@@ -35,7 +35,7 @@ const slugs = new Slugger()
  * Search a node for a toc.
  *
  * @param {Node} root
- * @param {RegExp} expression
+ * @param {RegExp|null} expression
  * @param {SearchOptions} settings
  * @returns {SearchResult}
  */
@@ -44,7 +44,7 @@ export function search(root, expression, settings) {
   const parents = convert(settings.parents || ((d) => d === root))
   /** @type {Array.<SearchEntry>} */
   const map = []
-  /** @type {number} */
+  /** @type {number|undefined} */
   let index
   /** @type {number} */
   let endIndex
@@ -60,7 +60,7 @@ export function search(root, expression, settings) {
   return {
     index: index || -1,
     // <sindresorhus/eslint-plugin-unicorn#980>
-    // @ts-ignore Looks like a parent.
+    // @ts-expect-error Looks like a parent.
     endIndex: index ? endIndex || root.children.length : -1, // eslint-disable-line unicorn/explicit-length-check
     map
   }
@@ -69,7 +69,7 @@ export function search(root, expression, settings) {
   function onheading(node, position, parent) {
     const value = toString(node, {includeImageAlt: false})
     /** @type {string} */
-    // @ts-ignore `hProperties` from <https://github.com/syntax-tree/mdast-util-to-hast>
+    // @ts-expect-error `hProperties` from <https://github.com/syntax-tree/mdast-util-to-hast>
     const id = node.data && node.data.hProperties && node.data.hProperties.id
     const slug = slugs.slug(id || value)
 
@@ -78,14 +78,19 @@ export function search(root, expression, settings) {
     }
 
     // Our opening heading.
-    if (expression && !index && expression.test(value)) {
+    if (position !== null && expression && !index && expression.test(value)) {
       index = position + 1
       opening = node
       return
     }
 
     // Our closing heading.
-    if (opening && !endIndex && node.depth <= opening.depth) {
+    if (
+      position !== null &&
+      opening &&
+      !endIndex &&
+      node.depth <= opening.depth
+    ) {
       endIndex = position
     }
 

test/index.js

@@ -27,7 +27,7 @@ test('mdast-util-toc', (t) => {
 
   t.throws(
     () => {
-      // @ts-ignore runtime.
+      // @ts-expect-error runtime.
       toc()
     },
     /Cannot read property 'children' of undefined/,

tsconfig.json

@@ -10,6 +10,7 @@
     "declaration": true,
     "emitDeclarationOnly": true,
     "allowSyntheticDefaultImports": true,
-    "skipLibCheck": true
+    "skipLibCheck": true,
+    "strict": true
   }
 }