Warning: This library is in public beta
⚠️
https://www.npmjs.com/package/@segment/analytics-node
- Node.js >= 14
# npm
npm install @segment/analytics-node
# yarn
yarn add @segment/analytics-node
# pnpm
pnpm install @segment/analytics-node
Assuming some express-like web framework.
import { Analytics } from '@segment/analytics-node'
// or, if you use require:
const { Analytics } = require('@segment/analytics-node')
// instantiation
const analytics = new Analytics({ writeKey: '<MY_WRITE_KEY>' })
app.post('/login', (req, res) => {
analytics.identify({
userId: req.body.userId,
previousId: req.body.previousId
})
res.sendStatus(200)
})
app.post('/cart', (req, res) => {
analytics.track({
userId: req.body.userId,
event: 'Add to cart',
properties: { productId: '123456' }
})
res.sendStatus(201)
});
Avoid losing events on exit!
- Call
.closeAndFlush()
to stop collecting new events and flush all existing events. - If a callback on an event call is included, this also waits for all callbacks to be called, and any of their subsequent promises to be resolved.
await analytics.closeAndFlush()
// or
await analytics.closeAndFlush({ timeout: 5000 }) // force resolve after 5000ms
const app = express()
const server = app.listen(3000)
const onExit = async () => {
await analytics.closeAndFlush()
server.close(() => {
console.log("Gracefully closing server...")
process.exit()
})
}
['SIGINT', 'SIGTERM'].forEach((code) => process.on(code, onExit))
If you absolutely need to preserve all possible events in the event of a forced timeout, even ones that came in after analytics.closeAndFlush()
was called, you can collect those events.
const unflushedEvents = []
analytics.on('call_after_close', (event) => unflushedEvents.push(events))
await analytics.closeAndFlush()
console.log(unflushedEvents) // all events that came in after closeAndFlush was called
See complete list of settings in the AnalyticsSettings interface.
const analytics = new Analytics({
writeKey: '<MY_WRITE_KEY>',
host: 'https://api.segment.io',
path: '/v1/batch',
maxRetries: 3,
maxEventsInBatch: 15,
flushInterval: 10000,
// ... and more!
})
For Business plans with access to Regional Segment, you can use the host configuration parameter to send data to the desired region:
Oregon (Default) — api.segment.io/v1 Dublin — events.eu1.segmentapis.com An example of setting the host to the EU endpoint using the Node library would be:
const analytics = new Analytics({
...
host: "https://events.eu1.segmentapis.com"
});
Our libraries are built to support high performance environments. That means it is safe to use our Node library on a web server that’s serving thousands of requests per second.
Every method you call does not result in an HTTP request, but is queued in memory instead. Messages are then flushed in batch in the background, which allows for much faster operation.
By default, our library will flush:
- Every 15 messages (controlled by
settings.maxEventsInBatch
). - If 10 seconds has passed since the last flush (controlled by
settings.flushInterval
)
There is a maximum of 500KB per batch request and 32KB per call.
If you don’t want to batch messages, you can turn batching off by setting the maxEventsInBatch
setting to 1, like so:
const analytics = new Analytics({
...
maxEventsInBatch: 1
});
Batching means that your message might not get sent right away. But every method call takes an optional callback, which you can use to know when a particular message is flushed from the queue, like so:
analytics.track({
userId: '019mr8mf4r',
event: 'Ultimate Played',
},
(err, ctx) => {
...
}
)
Subscribe and log all event delivery errors.
const analytics = new Analytics({ writeKey: '<MY_WRITE_KEY>' })
analytics.on('error', (err) => console.error(err))
You can see the complete list of emitted events in emitter.ts
analytics.on('error', (err) => console.error(err))
analytics.on('identify', (ctx) => console.log(ctx))
analytics.on('track', (ctx) => console.log(ctx))
analytics.on('http_request', (event) => console.log(event))
// when triggered, emits an event of the shape:
{
url: 'https://api.segment.io/v1/batch',
method: 'POST',
headers: {
'Content-Type': 'application/json',
...
},
body: '...',
}
Different parts of your application may require different types of batching, or even sending to multiple Segment sources. In that case, you can initialize multiple instances of Analytics with different settings:
const marketingAnalytics = new Analytics({ writeKey: 'MARKETING_WRITE_KEY' });
const appAnalytics = new Analytics({ writeKey: 'APP_WRITE_KEY' });
-
Double check that you’ve followed all the steps in the Quick Start.
-
Make sure that you’re calling a Segment API method once the library is successfully installed: identify, track, etc.
-
Log events.
['initialize', 'call_after_close',
'screen', 'identify', 'group',
'track', 'ready', 'alias',
'page', 'error', 'register',
'deregister'].forEach((event) => analytics.on(event, console.log)
- If you want to intercept / disable analytics for integration tests, you can use something like nock
// Note: nock will _not_ work if polyfill fetch with something like undici, as nock uses the http module. Undici has its own interception method.
import nock from 'nock'
nock('https://api.segment.io')
.post('/v1/batch')
.reply(201)
.persist()
- Named imports.
// old
import Analytics from 'analytics-node'
// new
import { Analytics } from '@segment/analytics-node'
- Instantiation now requires an object as the first argument.
// old
var analytics = new Analytics('YOUR_WRITE_KEY'); // not supported
// new!
const analytics = new Analytics({ writeKey: '<MY_WRITE_KEY>' })
- Graceful shutdown (See Graceful Shutdown section)
// old
await analytics.flush(function(err, batch) {
console.log('Flushed, and now this program can exit!');
});
// new
await analytics.closeAndFlush()
Other Differences:
- The
enable
configuration option has been removed-- see "Disabling Analytics" section - the
errorHandler
configuration option has been remove -- see "Error Handling" section flushAt
configuration option ->maxEventsInBatch
.callback
call signature is different
// old
(err, batch) => void
// new
(err, ctx) => void
- Undocumented behavior around
track
properties have been removed.
// old, undocumented behavior
analytics.track({
...
event: 'Ultimate Played',
myProp: 'abc'
})
// new
analytics.track({
...
event: 'Ultimate Played',
properties: {
myProp: 'abc'
}
})
- See segment's documentation for plugin architecture.
import type { Plugin } from '@segment/analytics-node'
export const lowercase: Plugin = {
name: 'Lowercase events',
type: 'enrichment',
version: '1.0.0',
isLoaded: () => true,
load: () => Promise.resolve(),
track: (ctx) => {
ctx.updateEvent('event', ctx.event.event.toLowerCase())
return ctx
}
}
analytics.register(lowercase)
The alias, group, identify, page and track calls can all be passed an object of integrations that lets you turn certain destinations on or off. By default all destinations are enabled.
Here’s an example with the integrations object shown:
analytics.track({
event: 'Membership Upgraded',
userId: '97234974',
integrations: {
'All': false,
'Vero': true,
'Google Analytics': false
}
})
In this case, we’re specifying that we want this track to only go to Vero. All: false says that no destination should be enabled unless otherwise specified. Vero: true turns on Vero, etc.
Destination flags are case sensitive and match the destination’s name in the docs (i.e. “AdLearn Open Platform”, “awe.sm”, “MailChimp”, etc.). In some cases, there may be several names for a destination; if that happens you’ll see a “Adding (destination name) to the Integrations Object” section in the destination’s doc page with a list of valid names.
Note:
-
Available at the business level, filtering track calls can be done right from the Segment UI on your source schema page. We recommend using the UI if possible since it’s a much simpler way of managing your filters and can be updated with no code changes on your side.
-
If you are on a grandfathered plan, events sent server-side that are filtered through the Segment dashboard will still count towards your API usage.
- AWS lambda execution environment is challenging for typically non-response-blocking async activites like tracking or logging, since the runtime terminates / freezes after a response is emitted.
Here is an example of using analytics.js within a handler:
const { Analytics } = require("@segment/analytics-node");
// since analytics has the potential to be stateful if there are any plugins added,
// to be on the safe side, we should instantiate a new instance of analytics on every request (the cost of instantiation is low).
const analytics = () => new Analytics({
maxEventsInBatch: 1,
writeKey: '<MY_WRITE_KEY>',
})
.on("error", console.error);
module.exports.handler = async (event) => {
...
// we need to await before returning, otherwise the lambda will exit before sending the request.
await new Promise((resolve) =>
analytics().track({ event: 'My Event', anonymousId: 'foo' }, resolve)
)
return {
statusCode: 200,
};
....
};