chore: working on chapter 6

06-coding-with-streams/22-combined-stream/.gitignore

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+*.gz.enc
+package-uppercase.json

06-coding-with-streams/22-combined-stream/README.md

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+# 22-combined-stream
+
+This example shows how to create a combined stream.
+
+## Run
+
+To run the example:
+
+```bash
+node archive.js <a_password> <path/to/a/file>
+```

06-coding-with-streams/22-combined-stream/archive.js

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+import { randomBytes } from 'node:crypto'
+import { createReadStream, createWriteStream } from 'node:fs'
+import { pipeline } from 'node:stream'
+import { createCompressAndEncrypt } from './combined-streams.js'
+
+const [, , password, source] = process.argv
+const iv = randomBytes(16)
+const destination = `${source}.gz.enc`
+
+pipeline(
+  createReadStream(source),
+  createCompressAndEncrypt(password, iv),
+  createWriteStream(destination),
+  err => {
+    if (err) {
+      console.error(err)
+      process.exit(1)
+    }
+    console.log(`${destination} created with iv: ${iv.toString('hex')}`)
+  }
+)

06-coding-with-streams/22-combined-stream/combined-streams.js

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+import { createCipheriv, createDecipheriv, scryptSync } from 'node:crypto'
+import { compose } from 'node:stream'
+import { createGunzip, createGzip } from 'node:zlib'
+
+function createKey(password) {
+  return scryptSync(password, 'salt', 24)
+}
+
+export function createCompressAndEncrypt(password, iv) {
+  const key = createKey(password)
+  const combinedStream = compose(
+    createGzip(),
+    createCipheriv('aes192', key, iv)
+  )
+  combinedStream.iv = iv
+
+  return combinedStream
+}
+
+export function createDecryptAndDecompress(password, iv) {
+  const key = createKey(password)
+  return compose(createDecipheriv('aes192', key, iv), createGunzip())
+}

06-coding-with-streams/22-combined-stream/package.json

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+{
+  "name": "22-combined-stream",
+  "version": "1.0.0",
+  "description": "This example shows how to create a combined stream",
+  "type": "module",
+  "scripts": {},
+  "engines": {
+    "node": ">=22"
+  },
+  "engineStrict": true,
+  "keywords": [],
+  "author": "Luciano Mammino and Mario Casciaro",
+  "license": "MIT",
+  "dependencies": {}
+}

06-coding-with-streams/22-combined-stream/pipe-and-pipeline-test.js

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+import assert from 'node:assert/strict'
+import { createReadStream, createWriteStream } from 'node:fs'
+import { Transform, pipeline } from 'node:stream'
+
+const streamA = createReadStream('package.json')
+const streamB = new Transform({
+  transform(chunk, _enc, done) {
+    this.push(chunk.toString().toUpperCase())
+    done()
+  },
+})
+const streamC = createWriteStream('package-uppercase.json')
+
+const pipelineReturn = pipeline(streamA, streamB, streamC, () => {
+  // handle errors here
+})
+// biome-ignore lint/suspicious/noMisplacedAssertion: Not an actual unit test
+assert.equal(streamC, pipelineReturn) // valid
+
+const pipeReturn = streamA.pipe(streamB).pipe(streamC)
+
+// biome-ignore lint/suspicious/noMisplacedAssertion: Not an actual unit test
+assert.equal(streamC, pipeReturn) // valid

06-coding-with-streams/22-combined-stream/unarchive.js

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+import { createReadStream, createWriteStream } from 'node:fs'
+import { pipeline } from 'node:stream'
+import { createDecryptAndDecompress } from './combined-streams.js'
+
+// usage: node unarchive.js <password> <ivHex> <sourceFile> <destFile>
+// example:
+//  node unarchive.js alovelypassword 158bc6bb3648afc1415371ae0c240715 package.json.gz.enc decoded-package.json
+const [, , password, ivHex, source, destination] = process.argv
+const iv = Buffer.from(ivHex, 'hex')
+
+pipeline(
+  createReadStream(source),
+  createDecryptAndDecompress(password, iv),
+  createWriteStream(destination),
+  err => {
+    if (err) {
+      console.error(err)
+      process.exit(1)
+    }
+    console.log(`${destination} created`)
+  }
+)

06-coding-with-streams/23-forking-streams/.gitignore

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+*.md5
+*.sha1

06-coding-with-streams/23-forking-streams/README.md

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+# 23-forking-streams
+
+This example shows how to fork a stream.
+
+## Run
+
+To run the example:
+
+```bash
+node generate-hashes.js <path/to/a/file>
+```

06-coding-with-streams/23-forking-streams/generate-hashes.js

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+import { createHash } from 'node:crypto'
+import { createReadStream, createWriteStream } from 'node:fs'
+
+const filename = process.argv[2]
+const sha1Stream = createHash('sha1').setEncoding('hex')
+const md5Stream = createHash('md5').setEncoding('hex')
+
+const inputStream = createReadStream(filename)
+
+inputStream.pipe(sha1Stream).pipe(createWriteStream(`${filename}.sha1`))
+
+inputStream.pipe(md5Stream).pipe(createWriteStream(`${filename}.md5`))

06-coding-with-streams/23-forking-streams/package.json

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+{
+  "name": "23-forking-streams",
+  "version": "1.0.0",
+  "description": "This example shows how to fork a stream.",
+  "type": "module",
+  "scripts": {},
+  "engines": {
+    "node": ">=22"
+  },
+  "engineStrict": true,
+  "keywords": [],
+  "author": "Luciano Mammino and Mario Casciaro",
+  "license": "MIT",
+  "dependencies": {}
+}

06-coding-with-streams/24-merging-streams/README.md

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+# 24-merging-streams
+
+This example shows how to merge streams.
+
+## Run
+
+To run the example:
+
+```bash
+node merge-lines.js <destination> <source1> <source2> <source3> ...
+```

06-coding-with-streams/24-merging-streams/merge-lines.js

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+import { createReadStream, createWriteStream } from 'node:fs'
+import { createInterface } from 'node:readline'
+import { Readable, Transform } from 'node:stream'
+
+const [, , dest, ...sources] = process.argv
+const destStream = createWriteStream(dest)
+
+let endCount = 0
+for (const source of sources) {
+  const sourceStream = createReadStream(source, { highWaterMark: 16 })
+  const linesStream = Readable.from(createInterface({ input: sourceStream }))
+  const addLineEnd = new Transform({
+    transform(chunk, _encoding, cb) {
+      cb(null, `${chunk}\n`)
+    },
+  })
+
+  sourceStream.on('end', () => {
+    if (++endCount === sources.length) {
+      destStream.end()
+      console.log(`${dest} created`)
+    }
+  })
+  linesStream.pipe(addLineEnd).pipe(destStream, { end: false })
+}

06-coding-with-streams/24-merging-streams/package.json

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+{
+  "name": "24-merging-streams",
+  "version": "1.0.0",
+  "description": "This example shows how to merge streams",
+  "type": "module",
+  "scripts": {},
+  "engines": {
+    "node": ">=22"
+  },
+  "engineStrict": true,
+  "keywords": [],
+  "author": "Luciano Mammino and Mario Casciaro",
+  "license": "MIT",
+  "dependencies": {}
+}