feat: concurrent is better than parallel :)

Author: lmammino

06-coding-with-streams/18-sequential-execution/concat-files.js

@@ -11,7 +11,11 @@ export function concatFiles(dest, files) {
           transform(filename, _enc, done) {
             const src = createReadStream(filename)
             src.pipe(destStream, { end: false })
+            // same as ((err) => done(err))
+            // propagates the error
             src.on('error', done)
+            // same as (() => done())
+            // propagates correct completion
             src.on('end', done)
           },
         })

06-coding-with-streams/19-unordered-parallel-execution/.gitignore renamed to 06-coding-with-streams/19-unordered-concurrent-execution/.gitignore

@@ -1,6 +1,6 @@
-# 19-unordered-parallel-execution
+# 19-unordered-concurrent-execution
 
-This example shows how to create a parallel execution flow using streams.
+This example shows how to create a concurrent execution flow using streams.
 
 ## Run
 

06-coding-with-streams/19-unordered-parallel-execution/README.md renamed to 06-coding-with-streams/19-unordered-concurrent-execution/README.md

@@ -1,13 +1,13 @@
 import { createReadStream, createWriteStream } from 'node:fs'
 import { createInterface } from 'node:readline'
 import { pipeline } from 'node:stream/promises'
-import { ParallelStream } from './parallel-stream.js'
+import { ConcurrentStream } from './concurrent-stream.js'
 
 const inputFile = createReadStream(process.argv[2])
 const fileLines = createInterface({
   input: inputFile,
 })
-const checkUrls = new ParallelStream(async (url, _enc, push, done) => {
+const checkUrls = new ConcurrentStream(async (url, _enc, push, done) => {
   if (!url) {
     return done()
   }

06-coding-with-streams/19-unordered-parallel-execution/check-urls.js renamed to 06-coding-with-streams/19-unordered-concurrent-execution/check-urls.js

@@ -1,6 +1,6 @@
 import { Transform } from 'node:stream'
 
-export class ParallelStream extends Transform {
+export class ConcurrentStream extends Transform {
   constructor(userTransform, opts) {
     super({ objectMode: true, ...opts })
     this.userTransform = userTransform

06-coding-with-streams/19-unordered-parallel-execution/parallel-stream.js renamed to 06-coding-with-streams/19-unordered-concurrent-execution/concurrent-stream.js

@@ -1,7 +1,7 @@
 {
-  "name": "19-unordered-parallel-execution",
+  "name": "19-unordered-concurrent-execution",
   "version": "1.0.0",
-  "description": "This example shows how to create a parallel execution flow using streams",
+  "description": "This example shows how to create a concurrent execution flow using streams",
   "type": "module",
   "scripts": {},
   "engines": {

06-coding-with-streams/19-unordered-parallel-execution/package.json renamed to 06-coding-with-streams/19-unordered-concurrent-execution/package.json

@@ -1,6 +1,6 @@
-# 20-unordered-limited-parallel-execution
+# 20-unordered-limited-concurrent-execution
 
-This example shows how to create a limited parallel execution flow using
+This example shows how to create a limited concurrent execution flow using
 streams.
 
 ## Run

06-coding-with-streams/19-unordered-parallel-execution/urls.txt renamed to 06-coding-with-streams/19-unordered-concurrent-execution/urls.txt

@@ -1,20 +1,24 @@
 import { createReadStream, createWriteStream } from 'node:fs'
 import { createInterface } from 'node:readline'
 import { pipeline } from 'node:stream/promises'
-import { LimitedParallelStream } from './limited-parallel-stream.js'
+import { LimitedConcurrentStream } from './limited-concurrent-stream.js'
 
 const inputFile = createReadStream(process.argv[2])
 const fileLines = createInterface({
   input: inputFile,
 })
-const checkUrls = new LimitedParallelStream(
+const checkUrls = new LimitedConcurrentStream(
   8,
   async (url, _enc, push, done) => {
     if (!url) {
       return done()
     }
     try {
-      await fetch(url, { method: 'HEAD', timeout: 5 * 1000 })
+      await fetch(url, {
+        method: 'HEAD',
+        timeout: 5000,
+        signal: AbortSignal.timeout(5000),
+      })
       push(`${url} is up\n`)
     } catch (err) {
       push(`${url} is down: ${err}\n`)