feat: add new encoding for file option to from file system (#68)

* feat: add new encoding for file option to from file system

* fix: default to null if no encoding is specified

* test: add tests for encoding

* feat: add encoding to metadata options

src/file-system.ts

@@ -58,8 +58,30 @@ export interface FromFileSystemOptions {
    * ```
    */
   extras?: DirectoryJSON;
+
+  /**
+   * A function that determines the encoding to be used for a file.
+   * @default utf-8
+   *
+   * @example
+   * ```ts
+   * const files = await fromFileSystem("path/to/dir", {
+   *  getEncodingForFile: (path) => "utf-8",
+   * });
+   * ```
+   */
+  getEncodingForFile?: EncodingForFileFn;
 }
 
+const DEFAULT_ENCODING_FOR_FILE_FN = () => "utf-8" as BufferEncoding;
+
+/**
+ * A function type that determines the encoding for a given file path.
+ * @param {string} path - The path to the file.
+ * @returns {BufferEncoding | null} The encoding to be used for the file, as a {@link BufferEncoding}.
+ */
+export type EncodingForFileFn = (path: string) => BufferEncoding | null;
+
 /**
  * Processes a directory and its contents recursively, creating a JSON representation of the file system.
  *
@@ -97,7 +119,7 @@ async function processDirectory(
     } else if (options.followLinks && file.isSymbolicLink()) {
       files[filePath] = symlink(await readlink(fullPath));
     } else {
-      files[filePath] = await readFile(fullPath, "utf8");
+      files[filePath] = await readFile(fullPath, options.getEncodingForFile(fullPath));
     }
   }
 
@@ -141,7 +163,7 @@ function processDirectorySync(
     } else if (options.followLinks && file.isSymbolicLink()) {
       files[filePath] = symlink(readlinkSync(fullPath));
     } else {
-      files[filePath] = readFileSync(fullPath, "utf-8");
+      files[filePath] = readFileSync(fullPath, options.getEncodingForFile(fullPath));
     }
   }
 
@@ -173,12 +195,12 @@ export async function fromFileSystem(
     return {};
   }
 
-  const processOptions = {
+  const files = await processDirectory(path, {
     ignore: options?.ignore ?? [],
     followLinks: options?.followLinks ?? true,
-  };
+    getEncodingForFile: options?.getEncodingForFile ?? DEFAULT_ENCODING_FOR_FILE_FN,
+  });
 
-  const files = await processDirectory(path, processOptions);
   return {
     ...files,
     ...options?.extras,
@@ -210,12 +232,12 @@ export function fromFileSystemSync(
     return {};
   }
 
-  const processOptions = {
+  const files = processDirectorySync(path, {
     ignore: options?.ignore ?? [],
     followLinks: options?.followLinks ?? true,
-  };
+    getEncodingForFile: options?.getEncodingForFile ?? DEFAULT_ENCODING_FOR_FILE_FN,
+  });
 
-  const files = processDirectorySync(path, processOptions);
   return {
     ...files,
     ...options?.extras,

src/index.ts

@@ -23,7 +23,7 @@ export {
   FIXTURE_TYPE_LINK_SYMBOL,
   FIXTURE_TYPE_SYMLINK_SYMBOL,
 } from "./constants";
-export type { FromFileSystemOptions } from "./file-system";
+export type { EncodingForFileFn, FromFileSystemOptions } from "./file-system";
 export {
   fromFileSystem,
   fromFileSystemSync,

src/types.ts

@@ -76,7 +76,12 @@ export interface FSMetadata {
   /**
    * The POSIX permission of the file system entry.
    */
-  mode: number;
+  mode?: number;
+
+  /**
+   * The encoding of the file system entry.
+   */
+  encoding?: BufferEncoding | null;
 }
 
 /**

test/file-system.test.ts

@@ -160,4 +160,44 @@ describe("map file contents", () => {
 
     expect(result).toMatchObject(mockFiles);
   });
+
+  it("should use different encodings when using `getEncodingForFile`", async () => {
+    const mockFiles = {
+      "file.txt": "this is just a file!\n",
+      "README.md": "# vitest-testdirs\n",
+      "nested": {
+        "README.md": "# Nested Fixture Folder\n",
+        // eslint-disable-next-line node/prefer-global/buffer
+        "image.txt": Buffer.from([72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33, 10]),
+      },
+    };
+
+    const result = await fromFileSystem("./test/fixtures/file-system/test-dir", {
+      getEncodingForFile: (path) => {
+        return path.endsWith("image.txt") ? null : "utf8";
+      },
+    });
+
+    expect(result).toMatchObject(mockFiles);
+  });
+
+  it("should use different encodings when using `getEncodingForFile` (sync)", () => {
+    const mockFiles = {
+      "file.txt": "this is just a file!\n",
+      "README.md": "# vitest-testdirs\n",
+      "nested": {
+        "README.md": "# Nested Fixture Folder\n",
+        // eslint-disable-next-line node/prefer-global/buffer
+        "image.txt": Buffer.from([72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33, 10]),
+      },
+    };
+
+    const result = fromFileSystemSync("./test/fixtures/file-system/test-dir", {
+      getEncodingForFile: (path) => {
+        return path.endsWith("image.txt") ? null : "utf8";
+      },
+    });
+
+    expect(result).toMatchObject(mockFiles);
+  });
 });