Looks great!

BTW Can it handle unlimited data stream? For example, something like push-notification via WebSocket that emits an item for each server-side event. GraphQL subscriptions are exactly the case.

Here is a demo for streaming deserialization of Ruby's msgpack gem which is designed and developed by the MessagePack original author:

require "msgpack"
stream = StringIO.new([
 # each item is an independent, complete MessagePack item
 MessagePack.pack(true),
 MessagePack.pack(42),
 MessagePack.pack("foo"),
 MessagePack.pack("bar"),
].join(""))
u = MessagePack::Unpacker.new(stream)
u.each do |obj|
 p obj
end

It emits true, 42, "foo", "bar", respectively. Because there is no wrapper array, the MessagePack::Unpacker can handle unlimited data stream as long as data exist.

I see, no this is one is specifically for arrays, but I can add version what will support this kind of streams. It's pretty easy to do. But let's do it in separate PR, because it's different from this one.

Here is the version for decoding stream of objects

async *decodeStream(stream: AsyncIterable<ArrayLike<number> | Uint8Array>) {
 for await (const buffer of stream) {
 this.appendBuffer(buffer);
 try {
 while (true) {
 let result = this.decodeSync();
 yield result;
 }
 } catch (e) {
 if (!(e instanceof DataViewIndexOutOfBoundsError)) {
 throw e; // rethrow
 }
 // fallthrough
 }
 }
 }

Good! Can you add decodeStream() in this PR?

And can you add tests to keep test coverage?

Can I add tests in separate PR? :) I was going to start integrating this into our project today/tomorrow.
But I will add them for sure this week.

Let's add decodeStream in separate PR too because I want to test it first. And just to keep each PR for separate functional increment.

I will add tests for both decodeArrayStream and decodeStream during next days.

btw, does Karma tests requires any additionally setup in this project?
I fails with:

Error: socket hang up
 at createHangUpError (_http_client.js:343:17)
 at Socket.socketOnEnd (_http_client.js:444:23)
 at Socket.emit (events.js:205:15)
 at endReadableNT (_stream_readable.js:1137:12)
 at processTicksAndRejections (internal/process/task_queues.js:84:9) {
 code: 'ECONNRESET'
}

all the time

Nevermind. it's because of WebStrom. Works fine from terminal

OK! So you can add tests and others in separate PRs. Will merge it and release a new version!

BTW I use vscode to edit the code. Make sure npm run lint:fix to keep the code tidy!

Great! Wait for new version please. I need one more small change. I need to export Decoder and Encoder from index.ts. Are you good with it? I need to have access to raw decoder/encoder.
In our project we have custom package format that consist of

• number
• number
• number
• array

So I can't parse it using simple decode function. But it can be done by using Decoder directly