docs: add ipc example

Author: Kikobeats

examples/ipc/index.js

@@ -0,0 +1,31 @@
+'use strict'
+
+const path = require('path')
+const $ = require('../../src')
+
+const SCRIPT_PATH = path.resolve(__dirname, 'worker.js')
+
+const main = async () => {
+  const subprocess = $('node', [SCRIPT_PATH], {
+    detached: process.platform !== 'win32',
+    stdio: ['pipe', 'pipe', 'pipe', 'ipc']
+  })
+
+  const url = 'http://vercel.com'
+  const html = await fetch(url).then(res => res.text())
+
+  subprocess.send({ url, html })
+
+  const { promise, resolve, reject } = Promise.withResolvers()
+
+  subprocess.on('message', resolve)
+  subprocess.on('error', reject)
+  return promise
+}
+
+main()
+  .then(result => console.log(result))
+  .catch(error => {
+    console.error(error)
+    process.exit(1)
+  })

examples/ipc/package.json

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+{
+  "name": "@tinyspawn/process-message",
+  "private": true,
+  "devDependencies": {
+    "@mozilla/readability": "latest",
+    "happy-dom": "latest"
+  }
+}

examples/ipc/worker.js

@@ -0,0 +1,26 @@
+'use strict'
+
+const { Readability } = require('@mozilla/readability')
+
+const parseReader = reader => {
+  try {
+    return reader.parse()
+  } catch (_) {
+    return {}
+  }
+}
+
+const getDocument = ({ url, html }) => {
+  const { Window } = require('happy-dom')
+  const window = new Window({ url })
+  const document = window.document
+  document.documentElement.innerHTML = html
+  return document
+}
+
+process.on('message', async ({ url, html, readabilityOpts } = {}) => {
+  const document = getDocument({ url, html })
+  const reader = new Readability(document, readabilityOpts)
+  const result = parseReader(reader)
+  process.send(result, () => process.exit(0))
+})