feat: adding send/receive to Channel

Removing it from all ToneAudioNode's. Now it's just on the Channel Interface

Author: tambien

Tone/component/channel/Bus.js

@@ -61,5 +61,17 @@ describe("Channel", () => {
 			channelA.dispose();
 			channelB.dispose();
 		});
+
+		describe("bus", () => {
+			it("can connect two channels together by name", () => {
+				return PassAudio(input => {
+					const sendChannel = new Channel();
+					input.connect(sendChannel);
+					sendChannel.send("test");
+					const recvChannel = new Channel().toDestination();
+					recvChannel.receive("test");
+				});
+			});
+		});
 	});
 });

Tone/component/channel/Channel.test.ts

@@ -5,6 +5,7 @@ import { Solo } from "./Solo";
 import { PanVol } from "./PanVol";
 import { Param } from "../../core/context/Param";
 import { readOnly } from "../../core/util/Interface";
+import { Gain } from "../../core/context/Gain";
 
 export interface ChannelOptions extends ToneAudioNodeOptions {
 	pan: AudioRange;
@@ -112,6 +113,54 @@ export class Channel extends ToneAudioNode<ChannelOptions> {
 		this._panVol.mute = mute;
 	}
 
+	/**
+	 * Store the send/receive channels by name. 
+	 */
+	private static buses: Map<string, Gain> = new Map();
+
+	/**
+	 * Get the gain node belonging to the bus name. Create it if
+	 * it doesn't exist
+	 * @param name The bus name
+	 */
+	private _getBus(name: string): Gain {
+		if (!Channel.buses.has(name)) {
+			Channel.buses.set(name, new Gain({ context: this.context }));
+		}
+		return Channel.buses.get(name) as Gain;
+	}
+
+	/**
+	 * Send audio to another channel using a string. `send` is a lot like
+	 * [[connect]], except it uses a string instead of an object. This can 
+	 * be useful in large applications to decouple sections since [[send]]
+	 * and [[receive]] can be invoked separately in order to connect an object
+	 * @param name The channel name to send the audio
+	 * @param volume The amount of the signal to send. 
+	 * 	Defaults to 0db, i.e. send the entire signal
+	 * @returns Returns the gain node of this connection.
+	 */
+	send(name: string, volume: Decibels = 0): Gain<"decibels"> {
+		const bus = this._getBus(name);
+		const sendKnob = new Gain({
+			context: this.context,
+			units: "decibels",
+			gain: volume,
+		});
+		this.connect(sendKnob);
+		sendKnob.connect(bus);
+		return sendKnob;
+	}
+
+	/**
+	 * Receive audio from a channel which was connected with [[send]]. 
+	 * @param name The channel name to receive audio from.
+	 */
+	receive(name: string) {
+		const bus = this._getBus(name);
+		bus.connect(this);
+	}
+
 	dispose(): this {
 		super.dispose();
 		this._panVol.dispose();