Make file streams disposable

package.json

@@ -49,6 +49,7 @@
         "projects": [
             {
                 "displayName": "node",
+                "testEnvironment": "jest-environment-node-single-context",
                 "testMatch": [
                     "<rootDir>/lib/test/**/*.test.js"
                 ]
@@ -79,6 +80,7 @@
         "eslint-plugin-deprecation": "2.0.0",
         "eslint-plugin-simple-import-sort": "12.0.0",
         "jest": "29.7.0",
+        "jest-environment-node-single-context": "29.4.0",
         "rimraf": "5.0.5",
         "source-map-support": "0.5.21",
         "tmp-promise": "3.0.3",

src/main/node/FileInputStream.ts

@@ -8,7 +8,7 @@ import { FileHandle, open } from "fs/promises";
 /**
  * File input stream for Node.js.
  */
-export class FileInputStream extends ReadableStream<Uint8Array> {
+export class FileInputStream extends ReadableStream<Uint8Array> implements AsyncDisposable {
     /** The open file handle. Null if not yet opened. */
     private file: FileHandle | null;
 
@@ -55,4 +55,9 @@ export class FileInputStream extends ReadableStream<Uint8Array> {
             this.file = null;
         }
     }
+
+    /** @inheritDoc */
+    public [Symbol.asyncDispose](): PromiseLike<void> {
+        return this.close();
+    }
 }

src/main/node/FileOutputStream.ts

@@ -8,7 +8,7 @@ import { FileHandle, open } from "fs/promises";
 /**
  * File output stream for Node.js.
  */
-export class FileOutputStream extends WritableStream<Uint8Array> {
+export class FileOutputStream extends WritableStream<Uint8Array> implements AsyncDisposable {
     /**
      * Creates a new file output stream writing to the given file.
      *
@@ -30,4 +30,9 @@ export class FileOutputStream extends WritableStream<Uint8Array> {
             }
         });
     }
+
+    /** @inheritDoc */
+    public [Symbol.asyncDispose](): PromiseLike<void> {
+        return this.close();
+    }
 }

src/test/node/FileInputStream.test.ts

@@ -30,4 +30,13 @@ describe("FileInputStream", () => {
     it("can read bytes from given file with custom chunk size (500)", async () => {
         await testStream(new FileInputStream(resolve(__dirname, `../../../src/test/data/iliad_utf-8.txt`), 500), 500);
     });
+
+    it("is disposable", async () => {
+        let spy: jest.SpyInstance | null = null;
+        if (spy == null /* Always true, just here to create a block on which end the stream is disposed */) {
+            await using stream = new FileInputStream(resolve(__dirname, `../../../src/test/data/iliad_utf-8.txt`));
+            spy = jest.spyOn(stream, "close");
+        }
+        expect(spy).toHaveBeenCalledTimes(1);
+    });
 });

src/test/node/FileOutputStream.test.ts

@@ -25,4 +25,16 @@ describe("FileOutputStream", () => {
             await rm(tmpFile);
         }
     });
+
+    it("is disposable", async () => {
+        let spy: jest.SpyInstance;
+        const tmpFile = await tmpName();
+        try {
+            await using stream = new FileOutputStream(tmpFile);
+            spy = jest.spyOn(stream, "close");
+        } finally {
+            await rm(tmpFile);
+        }
+        expect(spy).toHaveBeenCalledTimes(1);
+    });
 });

tsconfig.json

@@ -16,7 +16,7 @@
         "experimentalDecorators": true,
         "emitDecoratorMetadata": true,
         "strict": true,
-        "strictPropertyInitialization": false,
+        "strictPropertyInitialization": true,
         "noUnusedLocals": true,
         "noUnusedParameters": false,
         "skipLibCheck": true,