Ampli for Javascript 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 provides autocompletion for events and properties defined in Data and enforces your event schemas in code to prevent bad instrumentation.

Amplitude Data supports tracking analytics events from browser apps written in JavaScript (ES6 and higher) and TypeScript (2.1 and higher). Ampli packages the generated tracking library as a CJS module.

Quickstart

1. (Prerequisite) Create a Tracking Plan in Amplitude Data

   Plan your events and properties in Amplitude Data.

2. Install the Amplitude SDK

npm install amplitude-js@^8.21.0

2. Install the Ampli CLI

npm install -g @amplitude/ampli

3. Pull the Ampli Wrapper into your project

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

4. Initialize the Ampli Wrapper

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

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

5. Identify users and set user properties

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

6. Track events with strongly typed methods and classes

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

7. Flush events before application exit

ampli.flush();

8. Verify implementation status with CLI

ampli status [--update]

Install the Amplitude SDK

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

npm install amplitude-js@^8.21.0

Install the Ampli CLI

You can install the Ampli CLI from Homebrew or NPM.

brew tap amplitude/ampli
brew install ampli

Pull the Ampli Wrapper into your project

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

ampli pull

API

Ampli generates a thin facade over the Amplitude SDK that provides convenience methods. The Ampli Wrapper also grants access to every method of the underlying Amplitude SDK through ampli.client. For details, refer to Wrapping the Amplitude SDK.

Load

Initialize Ampli in your code. The load() function requires an options object to configure the SDK's behavior:

Identify

Call identify() to identify a user in your app and associate all future events with their identity, or to set their properties.

Just as the Ampli Wrapper creates types for events and their properties, it creates types for user 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("groupType", "groupName");

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 has performed the specific event, then 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 could be 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 set for that user's groupType, including the corresponding user property value. groupType is a string. groupName can be either a string or an array of strings to show that a user is in multiple groups. For example, if Joe is in orgId 10 and 20, then the groupName is [10, 20].

Your code might look like this:

ampli.setGroup("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 is structured like this:

ampli.eventName(properties: EventNameProperties, options: EventOptions, extra: MiddlewareExtra)

The properties argument passes event properties.

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

For example, in the following code, your tracking plan contains an event called songPlayed. The event has two required properties: songId and songFavorited. The property type for songId is string, and songFavorited is a boolean. The event also defines an Amplitude field, deviceId. For more information, refer to Amplitude fields.

ampli.songPlayed(
  {
    songId: "songId", // string,
    songFavorited: true, // boolean
  },
  {
    deviceId: "a-device-id",
  },
  {
    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(
  new SongPlayed({
    songId: "songId", // string,
    songFavorited: true, // boolean
  }),
);

Flush

The Ampli wrapper queues events and sends them on an interval based on the configuration.

Call flush() to immediately send any pending events. The flush() method returns a promise you can use to ensure all pending events send before continuing. Call flush() before application exit.

ampli.flush();

Ampli CLI

Pull

The pull command downloads the Ampli Wrapper code to your project. Run the pull command from the project root.

ampli pull

Log in to your workspace when prompted and select a source.

➜ 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

For more information, refer to ampli pull.

Status

Verify that events are in your code with the status command:

ampli status [--update]

The output displays status and indicates what events are missing.

➜ 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

For more information, refer to ampli status.