From 1227ce70953903d60209e43283d8a1ffba1784a8 Mon Sep 17 00:00:00 2001
From: Jerry Kurian <jerrykurian@protonmail.com>
Date: Sat, 25 Jan 2020 12:33:09 -0500
Subject: [PATCH] Allow demux to be piped (mux)

---
 src/functions/demux.ts | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/functions/demux.ts b/src/functions/demux.ts
index 6435447..25e16bd 100644
--- a/src/functions/demux.ts
+++ b/src/functions/demux.ts
@@ -37,6 +37,7 @@ class Demux extends Writable {
     private streamsByKey: {
         [key: string]: DemuxStreams;
     };
+    private destination: Writable;
     private demuxer: (chunk: any) => string;
     private construct: (destKey?: string) => DemuxStreams;
     constructor(
@@ -55,8 +56,12 @@ class Demux extends Writable {
         const destKey = this.demuxer(chunk);
         if (this.streamsByKey[destKey] === undefined) {
             this.streamsByKey[destKey] = await this.construct(destKey);
+            if (this.destination !== undefined) {
+                (this.streamsByKey[destKey] as any).pipe(this.destination);
+            }
         }
-        if (!this.streamsByKey[destKey].write(chunk, encoding)) {
+        const writeRes = this.streamsByKey[destKey].write(chunk, encoding);
+        if (!writeRes) {
             this.streamsByKey[destKey].once("drain", () => {
                 cb();
             });
@@ -65,6 +70,11 @@ class Demux extends Writable {
         }
     }
 
+    public pipe(dest: any) {
+        this.destination = dest;
+        return dest;
+    }
+
     public on(event: string, cb: any) {
         switch (eventsTarget[event]) {
             case EventSubscription.Self: