Add support for JSX identifiers

Author: wooorm

index.js

@@ -1 +1,5 @@
+/**
+ * @typedef {import('./lib/index.js').Options} Options
+ */
+
 export {cont, name, start} from './lib/index.js'

lib/index.js

@@ -1,6 +1,18 @@
+/**
+ * @typedef Options
+ *   Configuration.
+ * @property {boolean | null | undefined} [jsx=false]
+ *   Support JSX identifiers (default: `false`).
+ */
+
 const startRe = /[$_\p{ID_Start}]/u
 const contRe = /[$_\u{200C}\u{200D}\p{ID_Continue}]/u
-const re = /^[$_\p{ID_Start}][$_\u{200C}\u{200D}\p{ID_Continue}]*$/u
+const contReJsx = /[-$_\u{200C}\u{200D}\p{ID_Continue}]/u
+const nameRe = /^[$_\p{ID_Start}][$_\u{200C}\u{200D}\p{ID_Continue}]*$/u
+const nameReJsx = /^[$_\p{ID_Start}][-$_\u{200C}\u{200D}\p{ID_Continue}]*$/u
+
+/** @type {Options} */
+const emptyOptions = {}
 
 /**
  * Checks if the given code point can start an identifier.
@@ -20,22 +32,30 @@ export function start(code) {
  *
  * @param {number | undefined} code
  *   Code point to check.
+ * @param {Options | null | undefined} [options]
+ *   Configuration (optional).
  * @returns {boolean}
  *   Whether `code` can continue an identifier.
  */
 // Note: `undefined` is supported so you can pass the result from `''.codePointAt`.
-export function cont(code) {
-  return code ? contRe.test(String.fromCodePoint(code)) : false
+export function cont(code, options) {
+  const settings = options || emptyOptions
+  const re = settings.jsx ? contReJsx : contRe
+  return code ? re.test(String.fromCodePoint(code)) : false
 }
 
 /**
  * Checks if the given value is a valid identifier name.
  *
  * @param {string} name
  *   Identifier to check.
+ * @param {Options | null | undefined} [options]
+ *   Configuration (optional).
  * @returns {boolean}
  *   Whether `name` can be an identifier.
  */
-export function name(name) {
+export function name(name, options) {
+  const settings = options || emptyOptions
+  const re = settings.jsx ? nameReJsx : nameRe
   return re.test(name)
 }

readme.md

@@ -17,9 +17,10 @@
 *   [Install](#install)
 *   [Use](#use)
 *   [API](#api)
-    *   [`cont(code)`](#contcode)
-    *   [`name(name)`](#namename)
+    *   [`cont(code[, options])`](#contcode-options)
+    *   [`name(name[, options])`](#namename-options)
     *   [`start(code)`](#startcode)
+    *   [Options](#options)
 *   [Types](#types)
 *   [Compatibility](#compatibility)
 *   [Related](#related)
@@ -78,27 +79,31 @@ This package exports the identifiers [`cont`][cont], [`name`][name], and
 [`start`][start].
 There is no default export.
 
-### `cont(code)`
+### `cont(code[, options])`
 
 Checks if the given code point can continue an identifier.
 
 ###### Parameters
 
 *   `code` (`number`)
     — code point to check
+*   `options` ([`Options`][api-options], optional)
+    — configuration
 
 ###### Returns
 
 Whether `code` can continue an identifier (`boolean`).
 
-### `name(name)`
+### `name(name[, options])`
 
 Checks if the given value is a valid identifier name.
 
 ###### Parameters
 
 *   `name` (`string`)
     — identifier to check
+*   `options` ([`Options`][api-options], optional)
+    — configuration
 
 ###### Returns
 
@@ -117,10 +122,19 @@ Checks if the given code point can start an identifier.
 
 Whether `code` can start an identifier (`boolean`).
 
+### Options
+
+Configuration (TypeScript type).
+
+###### Fields
+
+*   `jsx` (`boolean`, default: `false`)
+    — support JSX identifiers.
+
 ## Types
 
 This package is fully typed with [TypeScript][].
-It exports no additional types.
+It exports the additional type [`Options`][api-options].
 
 ## Compatibility
 
@@ -198,8 +212,10 @@ abide by its terms.
 
 [estree]: https://github.com/estree/estree
 
-[cont]: #contcode
+[cont]: #contcode-options
 
-[name]: #namename
+[name]: #namename-options
 
 [start]: #startcode
+
+[api-options]: #options

test.js

@@ -39,6 +39,14 @@ test('isIdentifierName', () => {
     'should say `0xd8_00 0xde_a7` (together 0x1_02_a7) is a cont code'
   )
   assert.ok(!cont(0xd8_00), 'should not say `0xd8_00` is a cont code')
+  assert.ok(
+    !cont('-'.codePointAt(0)),
+    'should not say `-` is a cont code normally'
+  )
+  assert.ok(
+    cont('-'.codePointAt(0), {jsx: true}),
+    'should say `-` is a cont code w/ `jsx: true`'
+  )
 
   assert.ok(!name(''), 'should not say `` (empty string) is a name')
   assert.ok(name('a'), 'should say `a` is a name')
@@ -52,4 +60,7 @@ test('isIdentifierName', () => {
   assert.ok(!name('-aaa'), 'should not say `-aaa` is a name')
   assert.ok(name('ಠ_ಠ'), 'should say `ಠ_ಠ` is a name')
   assert.ok(name('𐊧'), 'should say `𐊧` (0x1_02_a7) is a name')
+  assert.ok(!name('a-b'), 'should not say `a-b` is a name normally')
+  assert.ok(name('a-b', {jsx: true}), 'should say `a-b` is a jsx name')
+  assert.ok(name('a-', {jsx: true}), 'should say `a-` is a jsx name')
 })