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 & properties defined in Data and enforce 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). The generated tracking library is packaged 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

1npm install amplitude-js@^8.21.0

2. Install the Ampli CLI

1npm install -g @amplitude/ampli

3. Pull the Ampli Wrapper into your project

1ampli pull [--path ./src/ampli]

4. Initialize the Ampli Wrapper

1import { ampli } from './src/ampli';
2 
3ampli.load({ client: { apiKey: AMPLITUDE_API_KEY } });

5. Identify users and set user properties

1ampli.identify('user-id', {
2    userProp: 'A trait associated with this user'
3});

6. Track events with strongly typed methods and classes

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

7. Flush events before application exit

1ampli.flush();

8. Verify implementation status with CLI

1ampli status [--update]

Install the Amplitude SDK

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

1npm install amplitude-js@^8.21.0

1yarn add amplitude-js@^8.21.0

Install the Ampli CLI

You can install the Ampli CLI from Homebrew or NPM.

1brew tap amplitude/ampli
2brew install ampli

1npm install -g @amplitude/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. Ampli CLI commands are usually run from the project root directory.

1ampli pull

API

Ampli generates a thin facade over the Amplitude SDK which provides convenience methods. The Ampli Wrapper also grants access to every method of the underlying Amplitude SDK through ampli.client. More details.

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.

1ampli.identify('user-id', {
2  role: 'admin'
3});

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

1ampli.identify('user-id', {
2  role: 'admin'
3}, {
4  deviceId: 'my-device-id'
5});

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.

1ampli.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, and the corresponding user property value. groupType is a string, and 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:

1ampli.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:

1ampli.eventName(properties: EventNameProperties, options: EventOptions, extra: MiddlewareExtra)

The properties argument passes event properties.

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

For example, in the following code, your tracking plan contains an event called songPlayed. The event is defined with two required properties: songId and songFavorited. The property type for songId is string, and songFavorited is a boolean.

The event has an Amplitude field defined: deviceId. Learn more about Amplitude fields here.

1ampli.songPlayed( {
2  songId: 'songId', // string,
3  songFavorited: true, // boolean
4}, {
5  deviceId: 'a-device-id',
6}, {
7  myMiddleware: { myMiddlewareProp: "value to send to middleware" }
8});

Ampli also generates a class for each event.

1const myEventObject = new SongPlayed({
2  songId: 'songId', // string,
3  songFavorited: true, // boolean
4});

Track Event objects using Ampli track:

1ampli.track(new SongPlayed({
2  songId: 'songId', // string,
3  songFavorited: true, // boolean
4}));

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. This can be useful to call prior to application exit.

1ampli.flush();

Ampli CLI

Pull

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

1ampli pull

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

1➜ ampli pull
2Ampli project is not initialized. No existing `ampli.json` configuration found.
3? Create a new Ampli project here? Yes
4? Organization: Amplitude
5? Workspace: My Workspace
6? Source: My Source

Learn more about ampli pull.

Status

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

1ampli status [--update]

The output displays status and indicates what events are missing.

1➜ ampli status
2✘ Verifying event tracking implementation in source code
3 ✔ Song Played (1 location)
4 ✘ Song Stopped Called when a user stops playing a song.
5Events Tracked: 1 missed, 2 total

Learn more about ampli status.