Refactor code-style

*   Add support for `null` in API input types
*   Add more docs to JSDoc

Author: wooorm

index.js

@@ -8,64 +8,61 @@ const search = /[#.]/g
 /**
  * Create a hast element from a simple CSS selector.
  *
- * @param selector
+ * @template {string} Selector
+ *   Type of selector.
+ * @template {string} [DefaultTagName='div']
+ *   Type of default tag name.
+ * @param {Selector | null | undefined} [selector]
  *   A simple CSS selector.
+ *
  *   Can contain a tag-name (`foo`), classes (`.bar`), and an ID (`#baz`).
  *   Multiple classes are allowed.
  *   Uses the last ID if multiple IDs are found.
- * @param [defaultTagName='div']
- *   Tag name to use if `selector` does not specify one.
+ * @param {DefaultTagName | null | undefined} [defaultTagName='div']
+ *   Tag name to use if `selector` does not specify one (default: `'div'`).
+ * @returns {Element & {tagName: import('./extract.js').ExtractTagName<Selector, DefaultTagName>}}
+ *   Built element.
  */
-export const parseSelector =
-  /**
-   * @type {(
-   *  <Selector extends string, DefaultTagName extends string = 'div'>(selector?: Selector|null, defaultTagName?: DefaultTagName) => Element & {tagName: import('./extract.js').ExtractTagName<Selector, DefaultTagName>}
-   * )}
-   */
-  (
-    /**
-     * @param {string|null} [selector]
-     * @param {string} [defaultTagName='div']
-     * @returns {Element}
-     */
-    function (selector, defaultTagName = 'div') {
-      const value = selector || ''
-      /** @type {Properties} */
-      const props = {}
-      let start = 0
-      /** @type {string|undefined} */
-      let previous
-
-      while (start < value.length) {
-        search.lastIndex = start
-        const match = search.exec(value)
-        const subvalue = value.slice(start, match ? match.index : value.length)
+export function parseSelector(selector, defaultTagName) {
+  const value = selector || ''
+  /** @type {Properties} */
+  const props = {}
+  let start = 0
+  /** @type {string | undefined} */
+  let previous
+  /** @type {string | undefined} */
+  let tagName
 
-        if (subvalue) {
-          if (!previous) {
-            defaultTagName = subvalue
-          } else if (previous === '#') {
-            props.id = subvalue
-          } else if (Array.isArray(props.className)) {
-            props.className.push(subvalue)
-          } else {
-            props.className = [subvalue]
-          }
+  while (start < value.length) {
+    search.lastIndex = start
+    const match = search.exec(value)
+    const subvalue = value.slice(start, match ? match.index : value.length)
 
-          start += subvalue.length
-        }
-
-        if (match) {
-          previous = match[0]
-          start++
-        }
+    if (subvalue) {
+      if (!previous) {
+        tagName = subvalue
+      } else if (previous === '#') {
+        props.id = subvalue
+      } else if (Array.isArray(props.className)) {
+        props.className.push(subvalue)
+      } else {
+        props.className = [subvalue]
       }
 
-      return {
-        type: 'element',
-        tagName: defaultTagName,
-        properties: props,
-        children: []
-      }
+      start += subvalue.length
     }
-  )
+
+    if (match) {
+      previous = match[0]
+      start++
+    }
+  }
+
+  return {
+    type: 'element',
+    // @ts-expect-error: fine.
+    tagName: tagName || defaultTagName || 'div',
+    properties: props,
+    children: []
+  }
+}