chore: working on chapter 6

06-coding-with-streams/26-readable-stream-utilities/README.md

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+# 26-readable-stream-utilities
+
+This example shows how to use Readable stream util methods such as `.map()`,
+`.filter()`, and `reduce()`.
+
+## Run
+
+To run the example:
+
+```bash
+node index.js
+```

06-coding-with-streams/26-readable-stream-utilities/index.js

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+import { createReadStream } from 'node:fs'
+import { createInterface } from 'node:readline'
+import { Readable, compose } from 'node:stream'
+import { createGunzip } from 'node:zlib'
+
+const uncompressedData = compose(
+  createReadStream('data.csv.gz'),
+  createGunzip()
+)
+const byLine = Readable.from(createInterface({ input: uncompressedData }))
+
+const totalProfit = await byLine
+  .drop(1)
+  .map(chunk => {
+    const [type, country, profit] = chunk.toString().split(',')
+    return { type, country, profit: Number.parseFloat(profit) }
+  })
+  .filter(record => record.country === 'Italy')
+  .reduce((acc, record) => acc + record.profit, 0)
+
+console.log(totalProfit)

06-coding-with-streams/26-readable-stream-utilities/package.json

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+{
+  "name": "26-readable-stream-utilities",
+  "version": "1.0.0",
+  "description": "This example shows how to use Readable stream util methods such as `.map()`, `.filter()`, and `reduce()`",
+  "type": "module",
+  "scripts": {},
+  "engines": {
+    "node": ">=22"
+  },
+  "engineStrict": true,
+  "keywords": [],
+  "author": "Luciano Mammino and Mario Casciaro",
+  "license": "MIT",
+  "dependencies": {}
+}

06-coding-with-streams/27-web-streams/README.md

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+# 27-web-streams
+
+This example demonstrates interoperability between Node.js streams and Web
+Streams.
+
+## Run
+
+To run the examples:
+
+```bash
+node node-to-web.js
+node web-to-node.js
+```

06-coding-with-streams/27-web-streams/node-to-web.js

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+import { Readable, Transform, Writable } from 'node:stream'
+
+const nodeReadable = new Readable({
+  read() {
+    this.push('Hello, ')
+    this.push('world!')
+    this.push(null)
+  },
+})
+
+const webReadable = Readable.toWeb(nodeReadable)
+console.log(webReadable)
+
+const nodeWritable = new Writable({
+  write(chunk, _enc, cb) {
+    console.log(chunk.toString())
+    cb()
+  },
+})
+
+const webWritable = Writable.toWeb(nodeWritable)
+console.log(webWritable)
+
+const nodeTransform = new Transform({
+  transform(chunk, _enc, cb) {
+    cb(null, chunk.toString().toUpperCase())
+  },
+})
+
+const webTransform = Transform.toWeb(nodeTransform)
+console.log(webTransform)
+
+nodeReadable.pipe(process.stdout)
+webReadable.pipeTo(Writable.toWeb(process.stdout))

06-coding-with-streams/27-web-streams/package.json

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+{
+  "name": "27-web-streams",
+  "version": "1.0.0",
+  "description": "This example demonstrates interoperability between Node.js streams and Web Streams",
+  "type": "module",
+  "scripts": {},
+  "engines": {
+    "node": ">=22"
+  },
+  "engineStrict": true,
+  "keywords": [],
+  "author": "Luciano Mammino and Mario Casciaro",
+  "license": "MIT",
+  "dependencies": {}
+}

06-coding-with-streams/27-web-streams/web-to-node.js

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+import { Readable, Transform, Writable } from 'node:stream'
+import {
+  ReadableStream,
+  TransformStream,
+  WritableStream,
+} from 'node:stream/web'
+
+const webReadable = new ReadableStream({
+  start(controller) {
+    controller.enqueue('Hello, ')
+    controller.enqueue('world!')
+    controller.close()
+  },
+})
+
+const nodeReadable = Readable.fromWeb(webReadable)
+console.log(nodeReadable)
+
+const webWritable = new WritableStream({
+  write(chunk) {
+    console.log(chunk)
+  },
+})
+
+const nodeWritable = Writable.fromWeb(webWritable)
+console.log(nodeWritable)
+
+const webTransform = new TransformStream({
+  transform(chunk, controller) {
+    controller.enqueue(chunk.toString().toUpperCase())
+  },
+})
+
+const nodeTransform = Transform.fromWeb(webTransform)
+console.log(nodeTransform)

06-coding-with-streams/28-stream-consumers/README.md

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+# 28-stream-consumers
+
+This example demonstrates how to use Node.js stream consumers.
+
+## Run
+
+To run the examples:
+
+```bash
+node accumulate-http.js
+node accumulate-http-consumers.js
+node accumulate-http-fetch.js
+```

06-coding-with-streams/28-stream-consumers/accumulate-http-consumers.js

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+import { request } from 'node:https'
+import consumers from 'node:stream/consumers'
+
+const req = request(
+  'https://jsonplaceholder.typicode.com/todos/1',
+  async res => {
+    const data = await consumers.json(res)
+    console.log(data)
+  }
+)
+req.end()

06-coding-with-streams/28-stream-consumers/accumulate-http-fetch.js

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+const res = await fetch('https://jsonplaceholder.typicode.com/todos/1')
+const data = await res.json()
+console.log(data)

06-coding-with-streams/28-stream-consumers/accumulate-http.js

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+import { request } from 'node:https'
+
+const req = request('https://jsonplaceholder.typicode.com/todos/1', res => {
+  let data = ''
+  res.on('data', chunk => {
+    data += chunk
+  })
+  res.on('end', () => {
+    console.log(JSON.parse(data))
+  })
+})
+req.end()

06-coding-with-streams/28-stream-consumers/package.json

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+{
+  "name": "28-stream-consumers",
+  "version": "1.0.0",
+  "description": "This example demonstrates how to use Node.js stream consumers",
+  "type": "module",
+  "scripts": {},
+  "engines": {
+    "node": ">=22"
+  },
+  "engineStrict": true,
+  "keywords": [],
+  "author": "Luciano Mammino and Mario Casciaro",
+  "license": "MIT",
+  "dependencies": {}
+}