Ampli for Browser SDK 1.0

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.

Enable real-time type checking for JavaScript

JavaScript isn't a type-safe language, so 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 the Severity to Warning or Error based on the level of strictness you want.

Linting with Prettier

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

/* tslint:disable */

/* eslint-disable */

Prettier has no corresponding in-code directive. Instead, add the generated path/to/ampli to your .prettierignore file. You can get the path with ampli pull. For more information, refer to the Prettier documentation.

Quickstart

(Prerequisite) Create a Tracking Plan in Amplitude Data
Plan your events and properties in Amplitude Data.

Install the Amplitude SDK

shell

npm install @amplitude/analytics-browser

Install the Ampli CLI
shell
```
npm install -g @amplitude/ampli
```
Pull the Ampli Wrapper into your project
shell
```
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({ songId: "song-1" });
ampli.track(new SongPlayed({ songId: "song-2" }));

Flush events before application exit
js
```
ampli.flush();
```
Verify implementation status with CLI
shell
```
ampli status [--update]
```

Install the Amplitude SDK

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

bash

npm install @amplitude/analytics-browser

When you use Ampli in the browser, Amplitude recommends loading @amplitude/analytics-browser as a module rather than as a JavaScript snippet.

Install the Ampli CLI

You can install the Ampli CLI from Homebrew or NPM.

bash

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.

bash

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 more 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.

Option	Type	Required	Description
`disabled`	Boolean	No	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.configuration`	`Amplitude.Config`	No	Overrides the default configuration for the AmplitudeClient.

Example of initialization with load to override the default configuration:

ampli.load({
  client: {
    apiKey: AMPLITUDE_API_KEY,
    configuration: {
      minIdLength: 10,
    },
  },
});

Identify

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

The Ampli Wrapper creates types for user properties in the same way it creates types for events and their 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 allows you to 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.client.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 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 you set 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, overwrites any existing groupName value set for that user's groupType, and updates 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.client.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 structure looks like this:

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

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 has 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. For more information, refer to Amplitude fields.

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

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. Calling flush() is useful before application exit.

typescript

ampli.flush();

Plugin

Plugins allow you to extend Amplitude behavior, for example, modifying event properties (enrichment type) or sending to third-party APIs (destination type).

First, define your plugin. Enrichment Plugin example:

import {
  BrowserConfig,
  EnrichmentPlugin,
  Event,
} from "@amplitude/analytics-types";

export class AddEventIdPlugin implements EnrichmentPlugin {
  name = "add-event-id";
  type = "enrichment" as const;
  currentId = 100;

  /**
   * setup() is called on plugin installation
   * example: client.add(new AddEventIdPlugin());
   */
  setup(config: BrowserConfig): Promise<undefined> {
    this.config = config;
  }

  /**
   * execute() is called on each event instrumented
   * example: client.track('New Event');
   */
  execute(event: Event): Promise<Event> {
    event.event_id = this.currentId++;
    return event;
  }
}

Add your plugin after you initialize Ampli.

ampli.client.add(new AddEventIdPlugin());

Ampli CLI

Pull

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

bash

ampli pull

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

For more information, refer to ampli pull.

Status

Verify that events appear in your code 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

For more information, refer to ampli status.

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