From 52f296c2839b9fb09cd460d453534f312914d301 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jimmy=20W=C3=A4rting?= <jimmy@warting.se>
Date: Fri, 16 Jul 2021 00:33:00 +0200
Subject: [PATCH] Conditional loading (#104)

use good old cjs to conditionally load stuff in node only
---
 index.js    | 37 ++++---------------------------------
 streams.cjs | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 33 deletions(-)
 create mode 100644 streams.cjs

diff --git a/index.js b/index.js
index 9a453f6..2d83349 100644
--- a/index.js
+++ b/index.js
@@ -1,39 +1,11 @@
 
 // TODO (jimmywarting): in the feature use conditional loading with top level await (requires 14.x)
-// Node has recently added whatwg stream into core, want to use that instead when it becomes avalible.
+// Node has recently added whatwg stream into core, want to use that instead when it becomes available.
 
-import * as stream from 'web-streams-polyfill/dist/ponyfill.es2018.js'
-
-const ReadableStream = globalThis.ReadableStream || stream.ReadableStream
-const ByteLengthQueuingStrategy = globalThis.ByteLengthQueuingStrategy || stream.ReadableStream
+import './streams.cjs';
 
 /** @typedef {import('buffer').Blob} NodeBlob} */
 
-// Fix buffer.Blob's missing stream implantation
-import('buffer').then(m => {
-	if (m.Blob && !m.Blob.prototype.stream) {
-		m.Blob.prototype.stream = function name(params) {
-			let position = 0;
-			const blob = this;
-			const stratergy = new ByteLengthQueuingStrategy({ highWaterMark: POOL_SIZE });
-
-			return new ReadableStream({
-				type: "bytes",
-				async pull(ctrl) {
-					const chunk = blob.slice(position, Math.min(blob.size, position + POOL_SIZE));
-					const buffer = await chunk.arrayBuffer();
-					position += buffer.byteLength;
-					ctrl.enqueue(new Uint8Array(buffer))
-
-					if (position === blob.size) {
-						ctrl.close()
-					}
-				}
-			}, stratergy)
-		}
-	}
-}, () => {})
-
 // 64 KiB (same size chrome slice theirs blob into Uint8array's)
 const POOL_SIZE = 65536;
 
@@ -171,15 +143,14 @@ export default class Blob {
 
 	stream() {
 		const it = toIterator(this.#parts, true);
-		const stratergy = new ByteLengthQueuingStrategy({ highWaterMark: POOL_SIZE });
 
 		return new ReadableStream({
-			type: "bytes",
+			type: 'bytes',
 			async pull(ctrl) {
 				const chunk = await it.next();
 				chunk.done ? ctrl.close() : ctrl.enqueue(chunk.value);
 			}
-		}, stratergy)
+		})
 	}
 
 	/**
diff --git a/streams.cjs b/streams.cjs
new file mode 100644
index 0000000..80844ca
--- /dev/null
+++ b/streams.cjs
@@ -0,0 +1,34 @@
+// 64 KiB (same size chrome slice theirs blob into Uint8array's)
+const POOL_SIZE = 65536;
+
+if (!globalThis.ReadableStream) {
+  try {
+    Object.assign(globalThis, require('streasm/web'))
+  } catch (error) {
+    Object.assign(globalThis, require('web-streams-polyfill/dist/ponyfill.es2018.js'))
+  }
+}
+
+try {
+  const {Blob} = require('buffer')
+  if (Blob && !Blob.prototype.stream) {
+		Blob.prototype.stream = function name(params) {
+			let position = 0;
+			const blob = this;
+
+			return new ReadableStream({
+				type: 'bytes',
+				async pull(ctrl) {
+					const chunk = blob.slice(position, Math.min(blob.size, position + POOL_SIZE));
+					const buffer = await chunk.arrayBuffer();
+					position += buffer.byteLength;
+					ctrl.enqueue(new Uint8Array(buffer))
+
+					if (position === blob.size) {
+						ctrl.close()
+					}
+				}
+			})
+		}
+	}
+} catch (error) {}