Merge pull request #90 from shgysk8zer0/feature/streams

Add `ReadableStream.from()`

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [v0.4.9] - 2025-01-22
+
+### Added
+- Add `ReadableStream.from()` polyfill
+
 ## [v0.4.8] - 2024-12-20
 
 ### Added

browser.js

@@ -1,5 +1,5 @@
 /**
- * @copyright 2023-2024 Chris Zuber <[email protected]>
+ * @copyright 2023-2025 Chris Zuber <[email protected]>
  */
 import './globalThis.js';
 import './string.js';
@@ -12,6 +12,7 @@ import './function.js';
 import './url.js';
 import './number.js';
 import './iterator.js';
+import './streams.js';
 import './math.js';
 import './secure-context.js';
 import './navigator.js';

node.js

@@ -4,6 +4,7 @@ import './blob.js';
 import './errors.js';
 import './function.js';
 import './iterator.js';
+import './streams.js';
 import './map.js';
 import './math.js';
 import './object.js';

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@shgysk8zer0/polyfills",
-  "version": "0.4.8",
+  "version": "0.4.9",
   "private": false,
   "type": "module",
   "description": "A collection of JavaScript polyfills",

streams.js

@@ -0,0 +1,35 @@
+import { polyfillMethod } from './utils.js';
+
+polyfillMethod(ReadableStream, 'from', function from(anyIterable) {
+	if (anyIterable[Symbol.iterator] instanceof Function) {
+		return new ReadableStream({
+			start(controller) {
+				try {
+					for (const chunk of anyIterable) {
+						controller.enqueue(chunk);
+					}
+				} catch(err) {
+					controller.error(err);
+				} finally {
+					controller.close();
+				}
+			}
+		});
+	} else if (anyIterable[Symbol.asyncIterator] instanceof Function) {
+		return new ReadableStream({
+			async start(controller) {
+				try {
+					for await (const chunk of anyIterable) {
+						controller.enqueue(chunk);
+					}
+				} catch(err) {
+					controller.error(err);
+				} finally {
+					controller.close();
+				}
+			}
+		});
+	} else {
+		throw new TypeError('`ReadableStream.from()` requires an iterable source.');
+	}
+});

streams.test.js

@@ -0,0 +1,13 @@
+import './streams.js';
+import { describe, test } from 'node:test';
+import { strictEqual, throws } from 'node:assert';
+
+describe('Check iterator polyfills', () => {
+	test('Test `ReadableStream.from()` polyfill', async () => {
+		const text = 'Hello, World!';
+		const stream = ReadableStream.from(text).pipeThrough(new TextEncoderStream());
+
+		strictEqual(await new Response(stream).text(), text, 'Stream should result in the original text input.');
+		throws(() => ReadableStream.from(null), { name: 'TypeError' }, 'Should throw a `TypeError` for non-iterable objects.');
+	});
+});