Ampli for Node SDK

The Ampli Wrapper is a generated, strongly typed API for tracking Analytics events based on your Tracking Plan in Amplitude Data. The tracking library exposes a function for every event in your team's tracking plan. The function's arguments correspond to the event's properties.

Ampli can benefit your app by providing autocompletion for events and properties defined in Data and enforcing your event schemas in code to prevent bad instrumentation.

Enable real-time type checking for JavaScript

Because JavaScript isn't a type-safe language, static type checking isn't built in like TypeScript. Some common IDEs allow real-time type checks in JavaScript based on JSDoc.

For a better development experience, Ampli generates JSDocs for all methods and classes.

To enable real-time type checking in VSCode for JavaScript:

Go to Preferences > Settings, then search for checkJs.
Select JS/TS > Implicit Project Config: Check JS.

After you activate the setting, type errors appear directly in the IDE.

Jetbrains provides similar support:

Go to Preferences > Editor > Inspections > JavaScript and TypeScript > General.
In Signature mismatch and Type mismatch, set Severity to Warning or Error based on the strictness you want.

Linting with Prettier

To prevent linting errors for eslint and tslint, the SDK-generated files have the following to disable the linters:

/* tslint:disable */

/* eslint-disable */

There's no corresponding "in-code" functionality with Prettier. Instead, add the generated path/to/ampli to your .prettierignore file. You can get the path with ampli pull. Go to the Prettier documentation for more information.

Quick start

bash

npm install @amplitude/node@^1.10.2 @amplitude/identify@^1.10.2 @amplitude/types@^1.10.2

Install the Ampli CLI.

bash

npm install -g @amplitude/ampli

Pull the Ampli Wrapper into your project.

bash

ampli pull [--path ./src/ampli]

Initialize the Ampli Wrapper.

import { ampli } from "./src/ampli";

ampli.load({ client: { apiKey: AMPLITUDE_API_KEY } });

Identify users and set user properties.

ampli.identify("user-id", {
  userProp: "A trait associated with this user",
});

Track events with strongly typed methods and classes.

ampli.songPlayed('ampli-user-id', { songId: 'song-1' });
ampli.track('ampli-user-id', new SongPlayed({ songId: 'song-2' });

Flush events before application exit.

ampli.flush();

Verify implementation status with CLI.

bash

ampli status [--update]

Install the SDK

If you haven't already, install the core Amplitude SDK dependencies.

bash

npm install @amplitude/node@^1.10.2 @amplitude/identify@^1.10.2 @amplitude/types@^1.10.2

Install Ampli

You can install the Ampli CLI from Homebrew or NPM.

bash

npm install -g @amplitude/ampli

Pull the Ampli Wrapper into your project

Run the Ampli CLI pull command from your project root to log in to Amplitude Data and download the strongly typed Ampli Wrapper for your tracking plan.

bash

ampli pull

The CLI prompts you to log in to your workspace and select a source.

bash

➜ ampli pull
Ampli project is not initialized. No existing `ampli.json` configuration found.
? Create a new Ampli project here? Yes
? Organization: Amplitude
? Workspace: My Workspace
? Source: My Source

Initialize Ampli

Initialize Ampli in your code.

import { ampli } from "./ampli";
ampli.load({ client: { apiKey: AMPLITUDE_API_KEY } });

The load() function requires an options object to configure the SDK's behavior:

Option	Type	Required	Description
`disabled`	`Boolean`	optional	Specifies whether the Ampli Wrapper does any work. When `true`, all calls to the Ampli Wrapper are no-ops. Useful in local or development environments. Defaults to `false`.
`client.instance`	`AmplitudeClient`	required if `client.apiKey` isn't set	Specifies an Amplitude instance. By default Ampli creates an instance for you.
`client.apiKey`	`String`	required if `client.instance` isn't set	Specifies an API Key. This option overrides the default, which is the API Key configured in your tracking plan.
`client.options`	`Amplitude.Options`	optional	Overrides the default configuration for the AmplitudeClient.

Identify

Call identify() to set user properties. Ampli creates types for user properties, just as it does for events and event properties.

The identify() function accepts an optional userId, optional user properties, and optional options.

For example, your tracking plan contains a user property called role. The property's type is a string.

ampli.identify("user-id", {
  role: "Admin",
});

The options argument lets you pass Amplitude fields for this call, such as deviceId.

ampli.identify(
  "user-id",
  {
    role: "admin",
  },
  {
    deviceId: "my-device-id",
  },
);

Group

Call setGroup() to associate a user with their group (for example, their department or company). The setGroup() function accepts a required groupType and groupName.

ampli.setGroup("user-id", "Group name", "Group Value");

Amplitude supports assigning users to groups and performing queries, such as Count by Distinct, on those groups. If at least one member of the group performs the specific event, the count includes the group.

For example, you want to group your users based on what organization they're in by using an 'orgId'. Joe is in 'orgId' '10', and Sue is in 'orgId' '15'. Sue and Joe both perform a certain event. You can query their organizations in the Event Segmentation Chart.

When setting groups, define a groupType and groupName. In the previous example, 'orgId' is the groupType, and '10' and '15' are the values for groupName. Another example of a groupType is 'sport', with groupName values like 'tennis' and 'baseball'.

Setting a group also sets the groupType:groupName as a user property and overwrites any existing groupName value for that user's groupType. groupType is a string. groupName can be a string or an array of strings to indicate that a user is in multiple groups.

For example, if Joe is in 'orgId' '10' and '20', the groupName is '[10, 20]'.

Your code might look like this:

ampli.setGroup("user-id", "orgId", ["10", "20"]);

Track

To track an event, call the event's corresponding function. Every event in your tracking plan gets its own function in the Ampli Wrapper. The call uses this structure:

ampli.eventName(
 userId: string | undefined,
 properties: EventProperties,
 options: EventOptions,
 extra: MiddlewareExtra
)

userId: in multi-tenant, server environments, you must provide a userId for each tracking call to associate the event with a user.

properties: passes event properties specific to this event in the tracking plan.

The options argument lets you pass Amplitude fields, like price, quantity, and revenue.

The extra argument lets you pass data to middleware.

For example, your tracking plan contains an event called Song Played. The SDK generates the songPlayed function for the event, using camel case to make the name valid JavaScript. The event has two required properties: songId and songFavorited. The property type for songId is string, and songFavorited is a boolean.

The event has two Amplitude fields: price and quantity. Learn more about Amplitude fields. The event has one MiddlewareExtra: myMiddleware. Learn more about middleware.

ampli.songPlayed(
  "ampli-user-id",
  {
    songId: "songId", // string,
    songFavorited: true, // boolean
  },
  {
    price: 1.23,
    quantity: 2,
  },
  {
    myMiddleware: { myMiddlewareProp: "value to send to middleware" },
  },
);

Ampli also generates a class for each event.

const myEventObject = new SongPlayed({
  songId: "songId", // string,
  songFavorited: true, // boolean
});

Track Event objects using Ampli track:

ampli.track(
  "ampli-user-id",
  new SongPlayed({
    songId: "songId", // string,
    songFavorited: true, // boolean
  }),
);

Flush

The Ampli Wrapper queues events and sends them on an interval based on the configuration. Ampli flushes the buffer automatically when flushQueueSize or flushInterval reach their thresholds, so you don't need to call flush() for normal operation.

Call flush() to immediately send any pending events. The flush() method returns a promise that you can use to ensure Ampli sends all pending events before continuing. This is useful before the application exits.

ampli.flush();

Status

Verify that your code implements all tracked events with the status command:

bash

ampli status [--update]

The output displays status and indicates what events are missing.

bash

➜ ampli status
✘ Verifying event tracking implementation in source code
 ✔ Song Played (1 location)
 ✘ Song Stopped Called when a user stops playing a song.
Events Tracked: 1 missed, 2 total

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