Refactor code-style

.gitignore

@@ -4,3 +4,4 @@ node_modules/
 *.d.ts
 *.log
 yarn.lock
+!/index.d.ts

index.d.ts

@@ -0,0 +1,34 @@
+export type {Options} from './lib/index.js'
+
+export {default} from './lib/index.js'
+
+// Add custom data supported when `retext-emoji` is added.
+declare module 'nlcst-emoticon-modifier' {
+  // eslint-disable-next-line @typescript-eslint/consistent-type-definitions
+  interface EmoticonData {
+    /**
+     * Emoji of emoticon node (example: `'😀'`).
+     *
+     * Registered by `retext-emoji`.
+     */
+    emoji?: string
+    /**
+     * Short description of emoticon node (example: `'grinning face'`).
+     *
+     * Registered by `retext-emoji`.
+     */
+    description?: string
+    /**
+     * Name of emoji (example: `['grinning']`).
+     *
+     * Registered by `retext-emoji`.
+     */
+    names?: string[]
+    /**
+     * Tags of emoji (example: `['smile', 'happy']`).
+     *
+     * Registered by `retext-emoji`.
+     */
+    tags?: string[]
+  }
+}

index.js

@@ -1,5 +1,2 @@
-/**
- * @typedef {import('./lib/index.js').Options} Options
- */
-
+// Note: types exposed from `index.d.ts`.
 export {default} from './lib/index.js'

lib/index.js

@@ -1,73 +1,61 @@
 /**
+ * @typedef {import('gemoji').Gemoji} Gemoji
  * @typedef {import('nlcst').Root} Root
- *
- * @typedef {import('nlcst-emoticon-modifier')} DoNotTouchAsThisImportIncludesEmoticonsInTree
+ * @typedef {import('unified').Processor} Processor
+ */
+
+/**
+ * @callback Convert
+ *   Convert.
+ * @param {string} value
+ *   Input.
+ * @returns {string}
+ *   Output.
  *
  * @typedef Options
  *   Configuration (optional).
- * @property {'encode'|'decode'} [convert]
- *   If, and *how* to convert (`'encode'` or `'decode'`, optional).
- *
- *   When `encode` is given, converts short-codes and emoticons to their unicode
- *   equivalent (`:heart:` and `<3` to `❤️`).
- *
- *   When `decode` is given, converts unicode emoji and emoticons to their short-code
- *   equivalent (`❤️` and `<3` to `:heart:`).
+ * @property {'decode' | 'encode' | null | undefined} [convert]
+ *   Whether to decode (`❤️` and `<3` to `:heart:`), encode (`:heart:` and `<3`
+ *   to `❤️`), or do nothing (optional).
  */
 
+import {emoticon} from 'emoticon'
+import {gemoji} from 'gemoji'
+import {emojiModifier} from 'nlcst-emoji-modifier'
 import {affixEmoticonModifier} from 'nlcst-affix-emoticon-modifier'
 import {emoticonModifier} from 'nlcst-emoticon-modifier'
-import {emojiModifier} from 'nlcst-emoji-modifier'
 import {toString} from 'nlcst-to-string'
 import {visit} from 'unist-util-visit'
-import {emoticon} from 'emoticon'
-import {gemoji} from 'gemoji'
-
-const own = {}.hasOwnProperty
 
 const vs16 = 0xfe_0f
 
-/** @type {Record<string, gemoji[number]>} */
-const emoji2info = {}
+/** @type {Record<string, Gemoji>} */
+const emojiToInfo = {}
 /** @type {Record<string, string>} */
-const emoticon2emoji = {}
+const emoticonToEmoji = {}
 /** @type {Record<string, string>} */
-const gemoji2emoji = {}
-
-/**
- * Map of visitors.
- *
- * @type {Record<string, (value: string) => string>}
- */
-const fns = {
-  /**
-   * Change to an emoji.
-   *
-   * @param {string} emoji
-   * @returns {string}
-   */
-  encode: (emoji) => emoji,
-  /**
-   * Change to a GitHub emoji short-code.
-   *
-   * @param {string} emoji
-   * @returns {string}
-   */
-  decode: (emoji) => ':' + emoji2info[emoji].names[0] + ':'
-}
+const gemojiToEmoji = {}
 
 init()
 
+/** @type {Readonly<Options>} */
+const emptyOptions = {}
+
 /**
  * Plugin to support emoji, gemoji, and emoticons.
  *
- * @type {import('unified').Plugin<[Options?], Root>}
+ * @this {Processor}
+ *   Processor.
+ * @param {Readonly<Options> | null | undefined} [options]
+ *   Configuration (optional).
+ * @returns
+ *   Transform.
  */
 export default function retextEmoji(options) {
-  const convert = (options || {}).convert
-  /** @type {fns[keyof fns]|undefined} */
-  let fn
+  const settings = options || emptyOptions
+  const convert = settings.convert
 
+  // Register extensions to parser.
   let sentence = this.data('nlcstSentenceExtensions')
   let paragraph = this.data('nlcstParagraphExtensions')
 
@@ -82,38 +70,47 @@ export default function retextEmoji(options) {
   sentence.push(emojiModifier, emoticonModifier)
   paragraph.push(affixEmoticonModifier)
 
-  if (convert !== null && convert !== undefined) {
-    if (!Object.keys(fns).includes(convert)) {
-      throw new TypeError(
-        'Invalid `convert` value `' +
-          convert +
-          "`, expected `'encode'` or `'decode'`"
-      )
-    }
-
-    fn = fns[convert]
+  /** @type {Convert | undefined} */
+  let convertFn
+
+  if (convert === null || convert === undefined) {
+    // Empty.
+  } else if (convert === 'decode') {
+    convertFn = decode
+  } else if (convert === 'encode') {
+    convertFn = identity
+  } else {
+    throw new TypeError(
+      'Invalid `convert` value `' +
+        convert +
+        "`, expected `'decode'` or `'encode'`"
+    )
   }
 
-  return (node) => {
-    visit(node, 'EmoticonNode', (node) => {
+  /**
+   * Transform.
+   *
+   * @param {Root} tree
+   *   Tree.
+   * @returns {undefined}
+   *   Nothing.
+   */
+  return function (tree) {
+    visit(tree, 'EmoticonNode', function (node) {
       const emoji = parse(toString(node))
 
       if (!emoji) return
 
-      if (fn) {
-        node.value = fn(emoji)
+      if (convertFn) {
+        node.value = convertFn(emoji)
       }
 
-      const info = emoji2info[emoji]
+      const info = emojiToInfo[emoji]
       const data = node.data || (node.data = {})
-      // @ts-expect-error: to do: register extra data.
       data.emoji = info.emoji
-      // @ts-expect-error: to do: register extra data.
       data.description = info.description
-      // @ts-expect-error: to do: register extra data.
-      data.names = info.names.concat()
-      // @ts-expect-error: to do: register extra data.
-      data.tags = info.tags.concat()
+      data.names = [...info.names]
+      data.tags = [...info.tags]
     })
   }
 }
@@ -122,15 +119,18 @@ export default function retextEmoji(options) {
  * Map a value to an emoji.
  *
  * @param {string} value
+ *   Input.
+ * @returns {string | undefined}
+ *   Output.
  */
 function parse(value) {
-  if (own.call(emoji2info, value)) return value
-  if (own.call(emoticon2emoji, value)) return emoticon2emoji[value]
-  if (own.call(gemoji2emoji, value)) return gemoji2emoji[value]
+  if (Object.hasOwn(emojiToInfo, value)) return value
+  if (Object.hasOwn(emoticonToEmoji, value)) return emoticonToEmoji[value]
+  if (Object.hasOwn(gemojiToEmoji, value)) return gemojiToEmoji[value]
 
   if (value.charCodeAt(value.length - 1) === vs16) {
     const without = value.slice(0, -1)
-    if (own.call(emoji2info, without)) return without
+    if (Object.hasOwn(emojiToInfo, without)) return without
   }
 }
 
@@ -143,10 +143,10 @@ function init() {
     const values = info.names
     let offset = -1
 
-    emoji2info[info.emoji] = info
+    emojiToInfo[info.emoji] = info
 
     while (++offset < values.length) {
-      gemoji2emoji[':' + values[offset] + ':'] = info.emoji
+      gemojiToEmoji[':' + values[offset] + ':'] = info.emoji
     }
   }
 
@@ -157,7 +157,21 @@ function init() {
     let offset = -1
 
     while (++offset < info.emoticons.length) {
-      emoticon2emoji[info.emoticons[offset]] = info.emoji
+      emoticonToEmoji[info.emoticons[offset]] = info.emoji
     }
   }
 }
+
+/**
+ * @type {Convert}
+ */
+function decode(value) {
+  return ':' + emojiToInfo[value].names[0] + ':'
+}
+
+/**
+ * @type {Convert}
+ */
+function identity(value) {
+  return value
+}

package.json

@@ -84,7 +84,8 @@
   "xo": {
     "prettier": true,
     "rules": {
-      "unicorn/prefer-code-point": "off"
+      "unicorn/prefer-code-point": "off",
+      "unicorn/prefer-switch": "off"
     }
   }
 }

readme.md

@@ -137,7 +137,7 @@ import {visit} from 'unist-util-visit'
 /** @type {import('nlcst').Root} */
 const tree = getNlcstNodeSomeHow()
 
-visit(tree, (node) => {
+visit(tree, function (node) {
   // `node` can now be `Emoticon`.
 })
 ```

test.js

@@ -1,3 +1,7 @@
+/**
+ * @typedef {import('nlcst-emoticon-modifier').Emoticon} Emoticon
+ */
+
 import assert from 'node:assert/strict'
 import test from 'node:test'
 import {retext} from 'retext'
@@ -9,9 +13,9 @@ test('retext-emoji', async function (t) {
 
   await t.test('should throw when given invalid `convert`', async function () {
     assert.throws(function () {
-      // @ts-expect-error: runtime.
+      // @ts-expect-error: check how the runtime handles invalid `convert`.
       retext().use(retextEmoji, {convert: false}).freeze()
-    }, /Invalid `convert` value `false`, expected `'encode'` or `'decode'`/)
+    }, /Invalid `convert` value `false`, expected `'decode'` or `'encode'`/)
   })
 
   await t.test('should classify emoticons', async function () {
@@ -236,6 +240,8 @@ test('retext-emoji', async function (t) {
   })
 
   await t.test('should not overwrite existing data', async function () {
+    /** @type {Emoticon} */
+    // @ts-expect-error: unregistered data.
     const emoji = u('EmoticonNode', {data: {alpha: true, bravo: 2}}, ':+1:')
 
     await retext()

tsconfig.json

@@ -5,11 +5,11 @@
     "declaration": true,
     "emitDeclarationOnly": true,
     "exactOptionalPropertyTypes": true,
-    "lib": ["es2020"],
+    "lib": ["es2022"],
     "module": "node16",
     "strict": true,
     "target": "es2020"
   },
   "exclude": ["coverage/", "node_modules/"],
-  "include": ["**/*.js"]
+  "include": ["**/*.js", "index.d.ts"]
 }