thread-stream - npm Package Compare versions

Comparing version 3.1.0 to 3.2.0

.claude/settings.local.json

+{
+  "permissions": {
+    "allow": [
+      "Bash(npx tap:*)",
+      "Bash(node:*)",
+      "Bash(for i in 1 2 3 4 5)",
+      "Bash(do)",
+      "Bash(echo:*)",
+      "Bash(done)",
+      "Bash(npm test:*)"
+    ],
+    "deny": [],
+    "ask": []
+  }
+}

CLAUDE.md

+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+thread-stream is a library for streaming data to a Node.js Worker Thread. It uses SharedArrayBuffer and Atomics for efficient inter-thread communication, enabling high-performance data streaming to worker threads.
+
+## Build & Test Commands
+
+```bash
+npm test                    # Run linting (standard), type checking, and all tests
+npm run build               # Type check only (tsc --noEmit)
+npm run test:ci             # CI-specific test run
+
+# Run a single test file
+node --test test/<filename>.test.js
+node --test test/<filename>.test.ts  # For TypeScript tests
+
+# Lint
+npx standard
+```
+
+## Architecture
+
+### Core Components
+
+- **index.js**: Main `ThreadStream` class extending EventEmitter. Manages shared memory buffers, worker lifecycle, and provides stream-like write/flush/end API.
+
+- **lib/worker.js**: Runs inside the Worker Thread. Loads the user-provided destination module, reads from shared buffer, and writes to the destination stream.
+
+- **lib/indexes.js**: Defines shared buffer index constants (`WRITE_INDEX`, `READ_INDEX`) used for Atomics-based synchronization.
+
+- **lib/wait.js**: Provides `wait()` and `waitDiff()` utilities for async waiting on Atomics state changes with exponential backoff.
+
+### Shared Memory Communication
+
+The main thread and worker communicate via two SharedArrayBuffers:
+1. **stateBuf**: Int32Array for READ_INDEX and WRITE_INDEX positions
+2. **dataBuf**: Buffer for actual string data (default 4MB)
+
+Write flow: Main thread writes to dataBuf, updates WRITE_INDEX, worker reads data between READ_INDEX and WRITE_INDEX, updates READ_INDEX when consumed.
+
+### Worker Module Interface
+
+User-provided worker modules must export an async function that receives `workerData` and returns a writable stream:
+
+```js
+async function run(opts) {
+  const stream = fs.createWriteStream(opts.dest)
+  await once(stream, 'open')
+  return stream
+}
+module.exports = run
+```
+
+### Sync vs Async Modes
+
+- `sync: true`: Blocking writes using flushSync, waits for worker to consume
+- `sync: false` (default): Non-blocking writes with drain events when buffer fills
+
+## Code Style
+
+Uses [Standard](https://standardjs.com/) for linting. Test files in `test/ts/**/*` and `test/syntax-error.mjs` are excluded from linting.

test/message-without-code.js

+'use strict'
+
+const { Writable } = require('stream')
+const { parentPort } = require('worker_threads')
+
+async function run () {
+  parentPort.postMessage({
+    internal: 'watch-mode'
+  })
+
+  return new Writable({
+    autoDestroy: true,
+    write (chunk, enc, cb) {
+      cb()
+    }
+  })
+}
+
+module.exports = run

test/watch-mode.test.js

+'use strict'
+
+const { test } = require('tap')
+const { join } = require('path')
+const ThreadStream = require('..')
+
+test('ignores worker messages without a protocol code', function (t) {
+  t.plan(2)
+
+  const stream = new ThreadStream({
+    filename: join(__dirname, 'message-without-code.js'),
+    sync: false
+  })
+
+  const errors = []
+  stream.on('error', err => {
+    errors.push(err)
+  })
+
+  stream.on('ready', () => {
+    t.ok(stream.write('hello world\n'))
+    stream.end()
+  })
+
+  stream.on('finish', () => {
+    t.same(errors, [])
+  })
+})

index.js

@@ -11,3 +11,4 @@ 'use strict'
   WRITE_INDEX,
-  READ_INDEX
+  READ_INDEX,
+  SEQ_INDEX
 } = require('./lib/indexes')
@@ -22,2 +23,9 @@ const buffer = require('buffer')
 
+function updateState (stream, fn) {
+  Atomics.add(stream[kImpl].state, SEQ_INDEX, 1)
+  fn()
+  Atomics.add(stream[kImpl].state, SEQ_INDEX, 1)
+  Atomics.notify(stream[kImpl].state, SEQ_INDEX)
+}
+
 class FakeWeakRef {
@@ -125,4 +133,7 @@ constructor (value) {
 
-        Atomics.store(stream[kImpl].state, READ_INDEX, 0)
-        Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+        updateState(stream, () => {
+          Atomics.store(stream[kImpl].state, READ_INDEX, 0)
+          Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+        })
+        Atomics.notify(stream[kImpl].state, READ_INDEX)
 
@@ -147,4 +158,7 @@ // Find a toWrite length that fits the buffer
     stream.flush(() => {
-      Atomics.store(stream[kImpl].state, READ_INDEX, 0)
-      Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+      updateState(stream, () => {
+        Atomics.store(stream[kImpl].state, READ_INDEX, 0)
+        Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+      })
+      Atomics.notify(stream[kImpl].state, READ_INDEX)
       nextFlush(stream)
@@ -167,2 +181,8 @@ })
 
+  // Node.js watch mode may send internal worker messages that do not
+  // participate in thread-stream's worker protocol.
+  if (msg?.code == null) {
+    return
+  }
+
   switch (msg.code) {
@@ -409,4 +429,5 @@ case 'READY':
   stream[kImpl].data.write(data, current)
-  Atomics.store(stream[kImpl].state, WRITE_INDEX, current + length)
-  Atomics.notify(stream[kImpl].state, WRITE_INDEX)
+  updateState(stream, () => {
+    Atomics.store(stream[kImpl].state, WRITE_INDEX, current + length)
+  })
   cb()
@@ -428,5 +449,6 @@ return true
     // process._rawDebug('writing index')
-    Atomics.store(stream[kImpl].state, WRITE_INDEX, -1)
+    updateState(stream, () => {
+      Atomics.store(stream[kImpl].state, WRITE_INDEX, -1)
+    })
     // process._rawDebug(`(end) readIndex (${Atomics.load(stream.state, READ_INDEX)}) writeIndex (${Atomics.load(stream.state, WRITE_INDEX)})`)
-    Atomics.notify(stream[kImpl].state, WRITE_INDEX)
 
@@ -476,4 +498,7 @@ // Wait for the process to complete
       flushSync(stream)
-      Atomics.store(stream[kImpl].state, READ_INDEX, 0)
-      Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+      updateState(stream, () => {
+        Atomics.store(stream[kImpl].state, READ_INDEX, 0)
+        Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+      })
+      Atomics.notify(stream[kImpl].state, READ_INDEX)
       continue
@@ -494,4 +519,7 @@ } else if (leftover < 0) {
       flushSync(stream)
-      Atomics.store(stream[kImpl].state, READ_INDEX, 0)
-      Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+      updateState(stream, () => {
+        Atomics.store(stream[kImpl].state, READ_INDEX, 0)
+        Atomics.store(stream[kImpl].state, WRITE_INDEX, 0)
+      })
+      Atomics.notify(stream[kImpl].state, READ_INDEX)
 
@@ -498,0 +526,0 @@ // Find a toWrite length that fits the buffer

lib/indexes.js

 'use strict'
 
+const SEQ_INDEX = 2
 const WRITE_INDEX = 4
@@ -8,3 +9,4 @@ const READ_INDEX = 8
   WRITE_INDEX,
-  READ_INDEX
+  READ_INDEX,
+  SEQ_INDEX
 }

lib/worker.js

@@ -5,3 +5,3 @@ 'use strict'
 const { workerData, parentPort } = require('worker_threads')
-const { WRITE_INDEX, READ_INDEX } = require('./indexes')
+const { WRITE_INDEX, READ_INDEX, SEQ_INDEX } = require('./indexes')
 const { waitDiff } = require('./wait')
@@ -105,5 +105,21 @@
 
+function readState () {
+  while (true) {
+    const seq = Atomics.load(state, SEQ_INDEX)
+
+    if ((seq & 1) !== 0) {
+      continue
+    }
+
+    const current = Atomics.load(state, READ_INDEX)
+    const end = Atomics.load(state, WRITE_INDEX)
+
+    if (seq === Atomics.load(state, SEQ_INDEX)) {
+      return { current, end, seq }
+    }
+  }
+}
+
 function run () {
-  const current = Atomics.load(state, READ_INDEX)
-  const end = Atomics.load(state, WRITE_INDEX)
+  const { current, end, seq } = readState()
 
@@ -113,7 +129,3 @@ // process._rawDebug(`pre state ${current} ${end}`)
   if (end === current) {
-    if (end === data.length) {
-      waitDiff(state, READ_INDEX, end, Infinity, run)
-    } else {
-      waitDiff(state, WRITE_INDEX, end, Infinity, run)
-    }
+    waitDiff(state, SEQ_INDEX, seq, Infinity, run)
     return
@@ -120,0 +132,0 @@ }

package.json

 {
   "name": "thread-stream",
-  "version": "3.1.0",
+  "version": "3.2.0",
   "description": "A streaming way to send data to a Node.js Worker Thread",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -90,3 +90,4 @@ # thread-stream
 You can emit events on the ThreadStream from your worker using [`worker.parentPort.postMessage()`](https://nodejs.org/api/worker_threads.html#workerparentport).
-The message (JSON object) must have the following data structure:
+Messages that do not carry a thread-stream protocol `code` are ignored.
+For custom events, the message (JSON object) must have the following data structure:
 
@@ -93,0 +94,0 @@ ```js

test/base.test.js

@@ -11,5 +11,15 @@ 'use strict'
 
-test('base sync=true', function (t) {
-  t.plan(15)
+function readFileAsync (path) {
+  return new Promise((resolve, reject) => {
+    readFile(path, 'utf8', (err, data) => {
+      if (err) {
+        reject(err)
+        return
+      }
+      resolve(data)
+    })
+  })
+}
 
+test('base sync=true', async function (t) {
   const dest = file()
@@ -22,20 +32,8 @@ const stream = new ThreadStream({
 
+  const finish = once(stream, 'finish')
+  const close = once(stream, 'close')
+
   t.same(stream.writableObjectMode, false)
-
   t.same(stream.writableFinished, false)
-  stream.on('finish', () => {
-    t.same(stream.writableFinished, true)
-    readFile(dest, 'utf8', (err, data) => {
-      t.error(err)
-      t.equal(data, 'hello world\nsomething else\n')
-    })
-  })
-
   t.same(stream.closed, false)
-  stream.on('close', () => {
-    t.same(stream.closed, true)
-    t.notOk(stream.writable)
-    t.pass('close emitted')
-  })
-
   t.same(stream.writableNeedDrain, false)
@@ -49,7 +47,15 @@ t.ok(stream.write('hello world\n'))
   t.same(stream.writableEnded, true)
+
+  await finish
+  t.same(stream.writableFinished, true)
+
+  await close
+  t.same(stream.closed, true)
+  t.notOk(stream.writable)
+
+  const data = await readFileAsync(dest)
+  t.equal(data, 'hello world\nsomething else\n')
 })
 
-test('overflow sync=true', function (t) {
-  t.plan(3)
-
+test('overflow sync=true', async function (t) {
   const dest = file()
@@ -63,5 +69,5 @@ const stream = new ThreadStream({
 
+  const close = once(stream, 'close')
   let count = 0
 
-  // Write 10 chars, 20 times
   function write () {
@@ -74,3 +80,2 @@ if (count++ === 20) {
     stream.write('aaaaaaaaaa')
-    // do not wait for drain event
     setImmediate(write)
@@ -81,15 +86,8 @@ }
 
-  stream.on('finish', () => {
-    t.pass('finish emitted')
-  })
-
-  stream.on('close', () => {
-    readFile(dest, 'utf8', (err, data) => {
-      t.error(err)
-      t.equal(data.length, 200)
-    })
-  })
+  await close
+  const data = await readFileAsync(dest)
+  t.equal(data.length, 200)
 })
 
-test('overflow sync=false', function (t) {
+test('overflow sync=false', async function (t) {
   const dest = file()
@@ -103,2 +101,3 @@ const stream = new ThreadStream({
 
+  const close = once(stream, 'close')
   let count = 0
@@ -108,6 +107,4 @@
 
-  // Write 10 chars, 20 times
   function write () {
     if (count++ === 20) {
-      t.pass('end sent')
       stream.end()
@@ -120,3 +117,2 @@ return
     }
-    // do not wait for drain event
     setImmediate(write)
@@ -129,20 +125,11 @@ }
     t.same(stream.writableNeedDrain, false)
-    t.pass('drain')
   })
 
-  stream.on('finish', () => {
-    t.pass('finish emitted')
-  })
-
-  stream.on('close', () => {
-    readFile(dest, 'utf8', (err, data) => {
-      t.error(err)
-      t.equal(data.length, 200)
-      t.end()
-    })
-  })
+  await close
+  const data = await readFileAsync(dest)
+  t.equal(data.length, 200)
 })
 
 test('over the bufferSize at startup', function (t) {
-  t.plan(6)
+  t.plan(5)
 
@@ -164,6 +151,2 @@ const dest = file()
 
-  stream.on('close', () => {
-    t.pass('close emitted')
-  })
-
   t.ok(stream.write('hello'))
@@ -177,3 +160,3 @@ t.ok(stream.write(' world\n'))
 test('over the bufferSize at startup (async)', function (t) {
-  t.plan(6)
+  t.plan(5)
 
@@ -200,9 +183,7 @@ const dest = file()
   })
-
-  stream.on('close', () => {
-    t.pass('close emitted')
-  })
 })
 
 test('flushSync sync=false', function (t) {
+  t.plan(2)
+
   const dest = file()
@@ -216,28 +197,22 @@ const stream = new ThreadStream({
 
-  stream.on('drain', () => {
-    t.pass('drain')
-    stream.end()
+  stream.on('ready', () => {
+    for (let count = 0; count < 20; count++) {
+      stream.write('aaaaaaaaaa')
+    }
+
+    stream.flushSync()
+    setImmediate(() => {
+      stream.end()
+    })
   })
 
   stream.on('finish', () => {
-    t.pass('finish emitted')
-  })
-
-  stream.on('close', () => {
     readFile(dest, 'utf8', (err, data) => {
       t.error(err)
       t.equal(data.length, 200)
-      t.end()
     })
   })
-
-  for (let count = 0; count < 20; count++) {
-    stream.write('aaaaaaaaaa')
-  }
-  stream.flushSync()
 })
 
 test('pass down MessagePorts', async function (t) {
-  t.plan(3)
-
   const { port1, port2 } = new MessageChannel()
@@ -252,2 +227,3 @@ const stream = new ThreadStream({
   })
+
   t.teardown(() => {
@@ -261,9 +237,6 @@ stream.end()
   const [strings] = await once(port2, 'message')
-
   t.equal(strings, 'hello world\nsomething else\n')
 })
 
-test('destroy does not error', function (t) {
-  t.plan(5)
-
+test('destroy does not error', async function (t) {
   const dest = file()
@@ -277,19 +250,20 @@ const stream = new ThreadStream({
   stream.on('ready', () => {
-    t.pass('ready emitted')
     stream.worker.terminate()
   })
 
-  stream.on('error', (err) => {
-    t.equal(err.message, 'the worker thread exited')
+  const [err] = await once(stream, 'error')
+  t.equal(err.message, 'the worker thread exited')
+
+  await new Promise((resolve) => {
     stream.flush((err) => {
       t.equal(err.message, 'the worker has exited')
+      resolve()
     })
-    t.doesNotThrow(() => stream.flushSync())
-    t.doesNotThrow(() => stream.end())
   })
+
+  t.doesNotThrow(() => stream.flushSync())
+  t.doesNotThrow(() => stream.end())
 })
 
-test('syntax error', function (t) {
-  t.plan(1)
-
+test('syntax error', async function (t) {
   const stream = new ThreadStream({
@@ -299,5 +273,4 @@ filename: join(__dirname, 'syntax-error.mjs')
 
-  stream.on('error', (err) => {
-    t.equal(err.message, 'Unexpected end of input')
-  })
+  const [err] = await once(stream, 'error')
+  t.equal(err.message, 'Unexpected end of input')
 })

No alert changes

Improved metrics

Total package byte prevSize

74238

6.02%

Number of package files

62

6.9%

Lines of code

2100

3.24%

Number of lines in readme file

137

0.74%

No dependency changes