set up dev script with proper termination

packages/docs-new/scripts/dev.ts

@@ -0,0 +1,75 @@
+import browserSync from "browser-sync"
+import type { ExecaChildProcess } from "execa"
+import { execa } from "execa"
+import { watch } from "node:fs/promises"
+import pino from "pino"
+import waitOn from "wait-on"
+import packageJson from "../package.json"
+
+const console = pino()
+
+let app: ExecaChildProcess | undefined
+
+async function stopApp() {
+  if (app) {
+    if (app.pid != undefined) {
+      process.kill(-app.pid, "SIGINT")
+    } else {
+      app.kill("SIGINT")
+    }
+    await new Promise((resolve) => app?.once("close", resolve))
+  }
+}
+
+async function startApp() {
+  console.info(app ? "Restarting app..." : "Starting app...")
+
+  await stopApp()
+
+  const [command, ...flags] = packageJson.scripts.serve.split(/\s+/)
+  app = execa(command!, flags, {
+    stdio: "inherit",
+    detached: true,
+  })
+
+  app.catch((error) => {
+    if (error.signal !== "SIGINT") {
+      console.error(error)
+    }
+  })
+
+  await waitOn({ resources: ["tcp:localhost:3000"] })
+
+  console.info("App running")
+}
+
+const browser = browserSync.create()
+
+process.on("SIGINT", async () => {
+  console.info("Shutting down...")
+  await stopApp()
+  browser.exit()
+  process.exit()
+})
+
+await startApp()
+
+browser.emitter.on("init", () => {
+  console.info("Browsersync started")
+})
+browser.emitter.on("browser:reload", () => {
+  console.info("Browser reloaded")
+})
+
+browser.init({
+  proxy: "http://localhost:3000",
+  port: 3001,
+  ui: false,
+  logLevel: "silent",
+})
+
+for await (const info of watch("src", { recursive: true })) {
+  console.info(`Changed: ${info.filename}`)
+  await startApp()
+  browser.reload()
+}