Refactor code-style

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

Author: wooorm

index.js

@@ -1 +1,10 @@
+/**
+ * @typedef {import('./lib/index.js').Options} Options
+ */
+
+// To do: next major: remove.
+/**
+ * @typedef {Options} RemoveOptions
+ */
+
 export {remove} from './lib/index.js'

lib/index.js

@@ -1,30 +1,13 @@
 /**
  * @typedef {import('unist').Node} Node
  * @typedef {import('unist').Parent} Parent
- *
- * @typedef {string} Type
- * @typedef {Record<string, unknown>} Props
+ * @typedef {import('unist-util-is').Test} Test
  *
  * @typedef Options
- * @property {boolean} [cascade=true]
+ *   Configuration.
+ * @property {boolean | null | undefined} [cascade=true]
  *   Whether to drop parent nodes if they had children, but all their children
  *   were filtered out.
- *
- * @typedef {Options} RemoveOptions
- * @deprecated
- *   Use `Options` instead.
- */
-
-/**
- * Check if a node passes a test.
- *
- * @template {Node} Tree
- *   Node type that is checked for.
- * @callback TestFunction
- * @param {Tree} node
- * @param {number|null|undefined} [index]
- * @param {Parent|null|undefined} [parent]
- * @returns {boolean|void}
  */
 
 import {convert} from 'unist-util-is'
@@ -39,28 +22,29 @@ const empty = []
  *
  * @param tree
  *   Tree to change.
- * @param [options]
+ * @param options
  *   Configuration (optional).
- * @param [test]
+ * @param test
  *   `unist-util-is`-compatible test.
  * @returns
  *   The given `tree` without nodes that pass `test`.
+ *
  *   `null` is returned if `tree` itself didn’t pass the test or is cascaded
  *   away.
  */
 export const remove =
   /**
    * @type {(
-   *  (<Tree extends Node>(node: Tree, options: RemoveOptions, test: Type|Props|TestFunction<import('unist-util-visit-parents/complex-types.js').InclusiveDescendant<Tree>>|Array<Type|Props|TestFunction<import('unist-util-visit-parents/complex-types.js').InclusiveDescendant<Tree>>>) => Tree|null) &
-   *  (<Tree extends Node>(node: Tree, test: Type|Props|TestFunction<import('unist-util-visit-parents/complex-types.js').InclusiveDescendant<Tree>>|Array<Type|Props|TestFunction<import('unist-util-visit-parents/complex-types.js').InclusiveDescendant<Tree>>>) => Tree|null)
+   *  (<Tree extends Node>(node: Tree, options: Options, test: Test) => Tree | null) &
+   *  (<Tree extends Node>(node: Tree, test: Test) => Tree | null)
    * )}
    */
   (
     /**
      * @param {Node} tree
-     * @param {RemoveOptions} [options]
-     * @param {Type|Props|TestFunction<Node>|Array<Type|Props|TestFunction<Node>>} [test]
-     * @returns {Node|null}
+     * @param {Options | null | undefined} [options]
+     * @param {Test | null | undefined} [test]
+     * @returns {Node | null}
      */
     function (tree, options, test) {
       const is = convert(test || options)
@@ -76,9 +60,9 @@ export const remove =
        * For each composite node, modify its children array in-place.
        *
        * @param {Node} node
-       * @param {number|undefined} [index]
-       * @param {Parent|undefined} [parent]
-       * @returns {Node|null}
+       * @param {number | null | undefined} [index]
+       * @param {Parent | null | undefined} [parent]
+       * @returns {Node | null}
        */
       function preorder(node, index, parent) {
         /** @type {Array<Node>} */