feat: join

README.md

@@ -120,6 +120,19 @@ fromIterable(new Set([1, 2, 3]))
 ```
 </details>
 
+<details>
+<summary>join</summary>
+
+```javascript
+import { join } from '@ilteoood/re-flusso/join';
+
+.pipeThrough(
+    join('-')
+)
+
+```
+</details>
+
 <details>
 <summary>last</summary>
 

src/join.ts

@@ -0,0 +1,31 @@
+const joinNewItem =
+	(separator: string) =>
+	<T>(chunk: T) =>
+		`${separator}${chunk}`;
+
+export const join = (
+	separator = ",",
+	writableStrategy?: QueuingStrategy,
+	readableStrategy?: QueuingStrategy,
+) => {
+	let joinChunk = (chunk: string) => {
+		joinChunk = joinNewItem(separator);
+		return chunk;
+	};
+
+	let buffer = "";
+
+	return new TransformStream<string, string>(
+		{
+			transform(chunk, controller) {
+				buffer += joinChunk(chunk);
+			},
+			flush(controller) {
+				controller.enqueue(buffer);
+				buffer = "";
+			},
+		},
+		writableStrategy,
+		readableStrategy,
+	);
+};

test/join.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, test } from "vitest";
+import { fromIterable } from "../src/fromIterable";
+import { join } from "../src/join";
+import { pipeline } from "../src/pipeline";
+import { toArray } from "../src/toArray";
+
+describe("join", () => {
+	test("should join strings", async () => {
+		const destinationArray = [];
+
+		await pipeline(fromIterable([1, 2, 3]), join(), toArray(destinationArray));
+
+		expect(destinationArray).toEqual(["1,2,3"]);
+	});
+
+	test("should join strings with custom separator", async () => {
+		const destinationArray = [];
+
+		await pipeline(
+			fromIterable([1, 2, 3]),
+			join("-"),
+			toArray(destinationArray),
+		);
+
+		expect(destinationArray).toEqual(["1-2-3"]);
+	});
+
+	test("should not throw with objects", async () => {
+		const destinationArray = [];
+
+		await pipeline(
+			fromIterable([{ a: 1 }, { a: 2 }, { a: 3 }]),
+			join("-"),
+			toArray(destinationArray),
+		);
+
+		expect(destinationArray).toEqual([
+			"[object Object]-[object Object]-[object Object]",
+		]);
+	});
+});

test/ndjson.test.ts

@@ -10,7 +10,7 @@ describe("ndJson", () => {
 		it("should parse an ndJson string", async () => {
 			const destinationArray = [];
 			const response = await fetch(
-				"https://gist.githubusercontent.com/rfmcnally/0a5a16e09374da7dd478ffbe6ba52503/raw/095e75121f31a8b7dc88aa89dbd637a944ce264a/ndJson-sample.json",
+				"https://gist.githubusercontent.com/rfmcnally/0a5a16e09374da7dd478ffbe6ba52503/raw/095e75121f31a8b7dc88aa89dbd637a944ce264a/ndjson-sample.json",
 			);
 
 			await pipeline(