Refactor code-style

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

Author: wooorm

complex-types.d.ts

@@ -1,4 +1,4 @@
 // To do: next major: remove this file.
-export type {MdxjsEsm} from './index.js'
+export type {MdxjsEsm, MDXJSEsm} from './index.js'
 
 /// <reference types="./index.js" />

index.d.ts

@@ -25,6 +25,12 @@ export interface MdxjsEsm extends Literal {
   }
 }
 
+/**
+ * Deprecated: use the `MdxjsEsm` type instead.
+ */
+// eslint-disable-next-line @typescript-eslint/naming-convention
+export type MDXJSEsm = MdxjsEsm
+
 // Add nodes to content.
 declare module 'mdast' {
   // eslint-disable-next-line @typescript-eslint/consistent-type-definitions

lib/index.js

@@ -2,22 +2,30 @@
  * @typedef {import('mdast-util-from-markdown').CompileContext} CompileContext
  * @typedef {import('mdast-util-from-markdown').Extension} FromMarkdownExtension
  * @typedef {import('mdast-util-from-markdown').Handle} FromMarkdownHandle
- * @typedef {import('mdast-util-to-markdown').Options} ToMarkdownExtension
+ *
  * @typedef {import('mdast-util-to-markdown').Handle} ToMarkdownHandle
+ * @typedef {import('mdast-util-to-markdown').Options} ToMarkdownExtension
+ *
  * @typedef {import('estree-jsx').Program} Program
- * @typedef {import('../index.js').MdxjsEsm} MdxjsEsm
  *
- * @typedef {MdxjsEsm} MDXJSEsm
- *   Deprecated name, prefer `MdxjsEsm`.
+ * @typedef {import('../index.js').MdxjsEsm} MdxjsEsm
  */
 
-/** @type {FromMarkdownExtension} */
+/**
+ * Extension for `mdast-util-from-markdown` to enable MDX ESM.
+ *
+ * @type {FromMarkdownExtension}
+ */
 export const mdxjsEsmFromMarkdown = {
   enter: {mdxjsEsm: enterMdxjsEsm},
   exit: {mdxjsEsm: exitMdxjsEsm, mdxjsEsmData: exitMdxjsEsmData}
 }
 
-/** @type {ToMarkdownExtension} */
+/**
+ * Extension for `mdast-util-to-markdown` to enable MDX ESM.
+ *
+ * @type {ToMarkdownExtension}
+ */
 export const mdxjsEsmToMarkdown = {handlers: {mdxjsEsm: handleMdxjsEsm}}
 
 /**
@@ -36,7 +44,7 @@ function enterMdxjsEsm(token) {
 function exitMdxjsEsm(token) {
   const value = this.resume()
   const node = /** @type {MdxjsEsm} */ (this.exit(token))
-  /** @type {Program|undefined} */
+  /** @type {Program | undefined} */
   // @ts-expect-error: custom.
   const estree = token.estree