uaParser¶

"Mozilla/5.0 (Windows NT..." — let's find out what that actually means.

What is it?¶

uaParser decodes User-Agent strings into structured info: browser name, OS, device type. Useful for analytics, logging, or tailoring responses based on whether someone's on mobile or desktop.

Access it as modules.uaParser.

How to use¶

Pass a User-Agent string, get a structured object:

let ua = modules.uaParser.parse(
  "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36"
)
// {
//   browser: { name: "Chrome", version: "120.0.0.0", major: "120" },
//   os: { name: "Windows", version: "10" },
//   device: { model: "", type: "", vendor: "" }
// }

Sync — no await needed.

Methods¶

Method	Returns	Description
`parse(uaString)`	`object`	Parse a User-Agent into browser, OS, and device
`setUA(uaString)`	`UAParser`	Set UA on an instance (advanced usage)

Parsed object shape¶

Field	Description
`browser.name`	Browser name (Chrome, Firefox, Safari, …)
`browser.version`	Full version string
`browser.major`	Major version number
`os.name`	Operating system (Windows, macOS, Android, …)
`os.version`	OS version
`device.model`	Device model (often empty on desktop)
`device.type`	`"mobile"`, `"tablet"`, or `""` for desktop
`device.vendor`	Device manufacturer

Try it¶

Log visitor info from a webhook¶

Bot replies in chat. The User-Agent is often in the request headers:

let uaString = request.headers["user-agent"] || ""
let ua = modules.uaParser.parse(uaString)

let summary = [
  "Browser: " + (ua.browser.name || "Unknown"),
  "OS: " + (ua.os.name || "Unknown"),
  "Device: " + (ua.device.type || "desktop")
].join("\n")

Bot.sendMessage("Visitor info:\n" + summary)

Customize message for mobile users¶

let ua = modules.uaParser.parse(request.headers["user-agent"] || "")

if (ua.device.type === "mobile") {
  Bot.sendMessage("Tip: open our mini-app for the best mobile experience.")
} else {
  Bot.sendMessage("Welcome! Use /help to get started.")
}

Store analytics in db¶

let ua = modules.uaParser.parse(request.headers["user-agent"] || "")

db.bot.set("analytics/last_visit", {
  browser: ua.browser.name,
  os: ua.os.name,
  device: ua.device.type || "desktop",
  user: user.id,
  at: Date.now()
})

Notes¶

Sync — no await needed
Device fields are often empty for desktop browsers — that's normal
User-Agent strings can be spoofed; don't rely on them for security decisions
Official package: ua-parser-js on npm