fix(lib-storage): chunk from readable only when defined (#1886)

* fix: fix readable chunking to work with node 12+ readable interface

* fix: adding new line

* chore(lib-storage): style updates to readable-helper

Author: alexforsyth

Diff for: lib/storage/src/data-chunk/readable-helper.ts

@@ -4,27 +4,25 @@ import { Readable } from "stream";
 import { DEFAULT } from "../upload/defaults";
 import { DataPart } from "./yield-chunk";
 
-interface StreamChunk {
-  Body: Buffer;
-  ended: boolean;
-}
-
 export async function* chunkFromReadable(reader: Readable, chunkSize: number): AsyncGenerator<DataPart, void, unknown> {
   let partNumber = DEFAULT.MIN_PART_NUMBER;
   let oldBuffer = Buffer.from("");
   while (partNumber < DEFAULT.MAX_PART_NUMBER) {
-    reader.resume();
-    const result = await _chunkFromStream(reader, chunkSize, oldBuffer);
-    reader.pause();
+    let currentBuffer = oldBuffer;
+    if (reader.readable) {
+      reader.resume();
+      currentBuffer = await _chunkFromStream(reader, chunkSize, oldBuffer);
+      reader.pause();
+    }
 
     yield {
-      Body: result.Body.slice(0, chunkSize),
+      Body: currentBuffer.slice(0, chunkSize),
       PartNumber: partNumber,
     };
-    oldBuffer = result.Body.slice(chunkSize) as Buffer;
+    oldBuffer = currentBuffer.slice(chunkSize) as Buffer;
     partNumber += 1;
 
-    if (result.ended && oldBuffer.length == 0) {
+    if (!reader.readable && oldBuffer.length == 0) {
       return;
     }
   }
@@ -33,7 +31,11 @@ export async function* chunkFromReadable(reader: Readable, chunkSize: number): A
   }
 }
 
-function _chunkFromStream(stream: Readable, chunkSize: number, oldBuffer: Buffer): Promise<StreamChunk> {
+function _chunkFromStream(stream: Readable, chunkSize: number, oldBuffer: Buffer): Promise<Buffer> {
+  if (!stream.readable) {
+    return Promise.resolve(oldBuffer);
+  }
+
   let currentChunk = oldBuffer;
   return new Promise((resolve, reject) => {
     const cleanupListeners = () => {
@@ -44,12 +46,9 @@ function _chunkFromStream(stream: Readable, chunkSize: number, oldBuffer: Buffer
 
     stream.on("data", (chunk) => {
       currentChunk = Buffer.concat([currentChunk, Buffer.from(chunk)]);
-      if (currentChunk.length >= chunkSize) {
+      if (currentChunk.length >= chunkSize || !stream.readable) {
         cleanupListeners();
-        resolve({
-          Body: currentChunk,
-          ended: false,
-        });
+        resolve(currentChunk);
       }
     });
     stream.on("error", (err) => {
@@ -58,10 +57,7 @@ function _chunkFromStream(stream: Readable, chunkSize: number, oldBuffer: Buffer
     });
     stream.on("end", () => {
       cleanupListeners();
-      resolve({
-        Body: currentChunk,
-        ended: true,
-      });
+      resolve(currentChunk);
     });
   });
 }