docs: api

Signed-off-by: Lexus Drumgold <unicornware@flexdevelopment.llc>

Author: unicornware

README.md

@@ -18,6 +18,11 @@ File extension regex
 - [Install](#install)
 - [Use](#use)
 - [API](#api)
+  - [`EXT_DTS_REGEX`](#ext_dts_regex)
+  - [`EXT_JS_REGEX`](#ext_js_regex)
+  - [`EXT_JSON_REGEX`](#ext_json_regex)
+  - [`EXT_TS_REGEX`](#ext_ts_regex)
+  - [`extRegex(ext[, options])`](#extregexext-options)
 - [Types](#types)
   - [Interfaces](#interfaces)
 - [Related](#related)
@@ -64,7 +69,118 @@ yarn add @flex-development/ext-regex@flex-development/ext-regex
 
 ## API
 
-**TODO**: api documentation.
+This package exports the following identifiers:
+
+- [`EXT_DTS_REGEX`](#ext_dts_regex)
+- [`EXT_JS_REGEX`](#ext_js_regex)
+- [`EXT_JSON_REGEX`](#ext_json_regex)
+- [`EXT_TS_REGEX`](#ext_ts_regex)
+- [`extRegex`](#extregexext-options)
+
+There is no default export.
+
+### `EXT_DTS_REGEX`
+
+TypeScript declaration file extension regex.
+
+Supported extensions:
+
+- `.d.cts`
+- `.d.mts`
+- `.d.ts`
+
+Named capturing groups:
+
+- `type`: Letter between `'.'` and `'ts'` in file extension
+
+#### Source
+
+> [`src/regex/dts.ts`](src/regex/dts.ts)
+
+### `EXT_JS_REGEX`
+
+JavaScript file extension regex.
+
+Supported extensions:
+
+- `.cjs`
+- `.js`
+- `.jsx`
+- `.mjs`
+
+Named capturing groups:
+
+- `type`: Letter between `'.'` and `'js'` in file extension
+
+#### Source
+
+> [`src/regex/js.ts`](src/regex/js.ts)
+
+### `EXT_JSON_REGEX`
+
+JSON file extension regex.
+
+Supported extensions:
+
+- `.json`
+- `.json5`
+- `.jsonc`
+
+Named capturing groups:
+
+- `type`: Character after `'json'` in file extension
+
+#### Source
+
+> [`src/regex/json.ts`](src/regex/json.ts)
+
+### `EXT_TS_REGEX`
+
+TypeScript file extension regex.
+
+Supported extensions:
+
+- `.cts`
+- `.d.cts`
+- `.d.mts`
+- `.d.ts`
+- `.mts`
+- `.ts`
+- `.tsx`
+
+Named capturing groups:
+
+- `dts`: Letter `'d'` if extension is [declaration file extension](#ext_dts_regex)
+- `type`: Letter between `'.'` and `'ts'` in file extension
+
+#### Source
+
+> [`src/regex/ts.ts`](src/regex/ts.ts)
+
+### `extRegex(ext[, options])`
+
+Creates a regular expression matching the given file extension, `ext`.
+
+The file extension does not need to begin with a dot character (`'.'`). If it doesn't, however, it will be formatted
+before being converted into a regular expression pattern. The returned regular expression will match the formatted file
+extension instead.
+
+#### Parameters
+
+- `{string}` **`ext`** — File extension to evaluate
+- `{Options?}` **`[options]`** — Regular expression options
+
+#### Returns
+
+`{RegExp}` Regular expression matching `ext`.
+
+#### Throws
+
+`{errnode.NodeError<TypeError>}` If `ext` is not a string.
+
+#### Source
+
+> [`src/utils/ext-regex.ts`](src/utils/ext-regex.ts)
 
 ## Types
 

src/regex/dts.ts

@@ -12,7 +12,7 @@
  * - `.d.mts`
  * - `.d.ts`
  *
- * Captured groups:
+ * Named capturing groups:
  *
  * - `type`: Letter between `'.'` and `'ts'` in file extension
  *

src/regex/js.ts

@@ -1,5 +1,5 @@
 /**
- * @file Regular EXPRESSIONS - EXT_JS_REGEX
+ * @file Regular Expressions - EXT_JS_REGEX
  * @module ext-regex/regex/js
  */
 
@@ -13,7 +13,7 @@
  * - `.jsx`
  * - `.mjs`
  *
- * Captured groups:
+ * Named capturing groups:
  *
  * - `type`: Letter between `'.'` and `'js'` in file extension
  *

src/regex/json.ts

@@ -1,5 +1,5 @@
 /**
- * @file Regular EXPRESSIONS - EXT_JSON_REGEX
+ * @file Regular Expressions - EXT_JSON_REGEX
  * @module ext-regex/regex/json
  */
 
@@ -12,7 +12,7 @@
  * - `.json5`
  * - `.jsonc`
  *
- * Captured groups:
+ * Named capturing groups:
  *
  * - `type`: Character after `'json'` in file extension
  *

src/regex/ts.ts

@@ -1,5 +1,5 @@
 /**
- * @file Regular EXPRESSIONS - EXT_TS_REGEX
+ * @file Regular Expressions - EXT_TS_REGEX
  * @module ext-regex/regex/ts
  */
 
@@ -16,7 +16,7 @@
  * - `.ts`
  * - `.tsx`
  *
- * Captured groups:
+ * Named capturing groups:
  *
  * - `dts`: Letter `'d'` if extension is declaration file extension
  * - `type`: Letter between `'.'` and `'ts'` in file extension

src/utils/ext-regex.ts

@@ -5,14 +5,17 @@
 
 import type { Options } from '#src/interfaces'
 import * as internal from '#src/internal'
-import * as errnode from '@flex-development/errnode'
+import type * as errnode from '@flex-development/errnode'
 import * as pathe from '@flex-development/pathe'
 import { isNIL, type LiteralUnion } from '@flex-development/tutils'
 
 /**
  * Creates a regular expression matching the given file extension, `ext`.
  *
- * The file extension need not begin with a dot character (`'.'`).
+ * The file extension does not need to begin with a dot character (`'.'`). If it
+ * doesn't, however, it will be formatted before being converted into a regular
+ * expression pattern. The returned regular expression will match the formatted
+ * file extension instead.
  *
  * Throws `ERR_INVALID_ARG_TYPE` if the given file extension is not a string.
  *