From fdcbea3714c4b152156da4878c3382dd4431e198 Mon Sep 17 00:00:00 2001
From: garrettmichaelgeorge <garrett.michael.george@gmail.com>
Date: Wed, 17 Mar 2021 14:55:45 -0400
Subject: [PATCH] Add failing tests for fanIn

---
 Tone/core/context/ToneAudioNode.test.ts | 21 ++++++++++++++++++++-
 Tone/core/context/ToneAudioNode.ts      | 14 ++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/Tone/core/context/ToneAudioNode.test.ts b/Tone/core/context/ToneAudioNode.test.ts
index 02880753..d741e31c 100644
--- a/Tone/core/context/ToneAudioNode.test.ts
+++ b/Tone/core/context/ToneAudioNode.test.ts
@@ -3,7 +3,7 @@ import { Merge } from "Tone/component";
 import { Split } from "Tone/component/channel/Split";
 import { Oscillator } from "Tone/source";
 import { Gain } from "./Gain";
-import { connect, disconnect } from "./ToneAudioNode";
+import { connect, disconnect, fanIn } from "./ToneAudioNode";
 import { PassAudio } from "test/helper/PassAudio";
 import { Offline } from "test/helper/Offline";
 
@@ -218,6 +218,16 @@ describe("ToneAudioNode", () => {
 				disconnect(input);
 			}, false);
 		});
+
+		it("can fan in multiple nodes to a destination", async () => {
+			return PassAudio(input => {
+				const input0 = new Gain();
+				const input1 = new Gain();
+				const input2 = new Gain();
+				const output = new Gain();
+				fanIn(output, input0, input1, input2);
+			});
+		});
 		
 		it("can connect one channel to another", () => {
 			return PassAudio(input => {
@@ -320,6 +330,15 @@ describe("ToneAudioNode", () => {
 				disconnect(gain, output);
 			});
 		});
+
+		it("can fan in multiple nodes to a destination", async () => {
+			const output = new Gain();
+			const input0 = new Gain();
+			const input1 = new Gain();
+			const input2 = new Gain();
+			fanIn(output, input0, input1, input2);
+			expect(output.numberOfInputs).to.equal(3);
+		});
 	});
 
 });
diff --git a/Tone/core/context/ToneAudioNode.ts b/Tone/core/context/ToneAudioNode.ts
index da7a1727..976f9119 100644
--- a/Tone/core/context/ToneAudioNode.ts
+++ b/Tone/core/context/ToneAudioNode.ts
@@ -257,6 +257,7 @@ export abstract class ToneAudioNode<Options extends ToneAudioNodeOptions = ToneA
 		return this;
 	}
 
+
 	/**
 	 * Dispose and disconnect
 	 */
@@ -376,3 +377,16 @@ export function disconnect(
 		srcNode.disconnect();
 	}
 }
+
+/**
+ * connect the output of this node to the rest of the nodes in parallel.
+ * @example
+ * const player = new Tone.Player("https://tonejs.github.io/audio/drum-samples/conga-rhythm.mp3");
+ * const player1 = new Tone.Player("https://tonejs.github.io/audio/drum-samples/conga-rhythm.mp3");
+ * const filter = new Tone.Filter("G5").toDestination();
+ * // connect nodes to a common destination
+ * fanIn(filter, player, player1);
+ */
+export function fanIn(dstNode: InputNode, ...srcNodes: OutputNode[]): void {
+	srcNodes.forEach(srcNode => connect(srcNode, dstNode));
+}