Add exports of some useful types

index.js

@@ -1,5 +1,8 @@
 /**
  * @typedef {import('./lib/parse.js').Schema} Schema
+ * @typedef {import('./lib/parse.js').Extension} Extension
+ * @typedef {import('./lib/parse.js').Warning} Warning
+ * @typedef {import('./lib/parse.js').Options} Options
  */
 
 export {parse} from './lib/parse.js'

lib/parse.js

@@ -1,23 +1,29 @@
 /**
- * @typedef ParseOptions
+ * @callback Warning
+ * @param {string} reason
+ * @param {number} code
+ * @param {number} offset
+ * @returns {void}
+ *
+ * @typedef Options
  * @property {boolean} [normalize=true]
  * @property {boolean} [forgiving=false]
- * @property {(reason: string, code: number, offset: number) => void} [warning]
+ * @property {Warning} [warning]
  *
  * @typedef Extension
  * @property {string} singleton
  * @property {Array<string>} extensions
  *
  * @typedef Schema
- * @property {string|null} language
+ * @property {string|null|undefined} language
  * @property {Array<string>} extendedLanguageSubtags
- * @property {string|null} script
- * @property {string|null} region
+ * @property {string|null|undefined} script
+ * @property {string|null|undefined} region
  * @property {Array<string>} variants
  * @property {Array<Extension>} extensions
  * @property {Array<string>} privateuse
- * @property {string|null} irregular
- * @property {string|null} regular
+ * @property {string|null|undefined} irregular
+ * @property {string|null|undefined} regular
  */
 
 import {isAlphanumerical} from 'is-alphanumerical'
@@ -32,7 +38,7 @@ const own = {}.hasOwnProperty
  * Parse a BCP 47 language tag.
  *
  * @param {string} tag
- * @param {ParseOptions} [options]
+ * @param {Options} [options]
  * @returns {Schema}
  */
 export function parse(tag, options = {}) {

lib/stringify.js

@@ -7,7 +7,7 @@
  * Compile a language schema to a BCP 47 language tag.
  *
  * @param {Schema} schema
- * @returns {string|undefined}
+ * @returns {string}
  */
 export function stringify(schema = {}) {
  /** @type {Array<string>} */

readme.md

@@ -258,8 +258,8 @@ Called when an error occurs.
 ## Types
 
 This package is fully typed with [TypeScript][].
-It additionally exports the `Schema` type, which represents the structure of
-that interface.
+It exports additional `Schema`, `Extension`, `Warning`, and `Options` types that
+model their respective interfaces.
 
 ## Compatibility