feat(fs): #3243 add encoding option to readTextFile functions (#3244)

* feat(fs): #3243 add encoding option to readFile and readTextFile functions

* feat(fs): add encoding option to ReadFileOptions and update readTextFileLines functions

* add change file

Author: SeijiOkuda

.changes/change-pr-3244.md

@@ -0,0 +1,6 @@
+---
+"fs": minor
+"fs-js": minor
+---
+
+Add `encoding` option for `readTextFile` and `readTextFileLines`

plugins/fs/api-iife.js

@@ -723,6 +723,8 @@ async function readDir(
 interface ReadFileOptions {
   /** Base directory for `path` */
   baseDir?: BaseDirectory
+  /** Text encoding to use when reading a text file. Defaults to 'utf-8'. */
+  encoding?: string
 }
 
 /**
@@ -753,7 +755,7 @@ async function readFile(
 }
 
 /**
- * Reads and returns the entire contents of a file as UTF-8 string.
+ * Reads and returns the entire contents of a file as a string using the specified encoding (default: UTF-8).
  * @example
  * ```typescript
  * import { readTextFile, BaseDirectory } from '@tauri-apps/plugin-fs';
@@ -777,11 +779,11 @@ async function readTextFile(
 
   const bytes = arr instanceof ArrayBuffer ? arr : Uint8Array.from(arr)
 
-  return new TextDecoder().decode(bytes)
+  return new TextDecoder(options?.encoding ?? 'utf-8').decode(bytes)
 }
 
 /**
- * Returns an async {@linkcode AsyncIterableIterator} over the lines of a file as UTF-8 string.
+ * Returns an async {@linkcode AsyncIterableIterator} over the lines of a file, decoded using the specified encoding (default: UTF-8).
  * @example
  * ```typescript
  * import { readTextFileLines, BaseDirectory } from '@tauri-apps/plugin-fs';
@@ -838,7 +840,7 @@ async function readTextFileLines(
         return { value: null, done }
       }
 
-      const line = new TextDecoder().decode(
+      const line = new TextDecoder(options?.encoding ?? 'utf-8').decode(
         bytes.slice(0, bytes.byteLength - 1)
       )