About event and visitor functions

Event and visitor functions are invoked after the event or visitor is processed. You can use event and visitor functions to retrieve data from other systems, augment Tealium data, or send data to other endpoints. To retrieve data from other systems, the function typically requires authention for that system. For information on adding authentication to an event or visitor function, see Adding an Authentication to a Function.

Input to event and visitor functions

The Tealium module exports five named exports for event and visitor functions, as follows:

A function imports the named exports as follows:

import { auth, visitor, event, store, tealium } from "tealium";

The auth, store, and tealium objects are available to event and visitor functions. The event object is available when a function is triggered by an event feed and contains the event data. The visitor object is available when a function is triggered by a visitor feed and contains visitor data. For more information, see Event Object and Visitor Object.

Auth object: auth.get()

Functions require authentication to access some service providers, such as Facebook or Google. For more information, see Add an Authentication to a Function. When you add an authentication, an access token is returned.

The auth.get() method returns a string that contains a unique auto-generated ID for the authentication token. When a function makes an HTTP request using this token ID, it is automatically replaced with the token before the request is sent.

Tealium object: sendCollectEvent()

The sendCollectEvent() method sends an event to Tealium Collect HTTP API and returns a string.

The Response interface of the Tealium Collect HTTP API represents the response to a request. The response model is the same as for fetch API, except that the URL is not available in the result of the Tealium Collect HTTP API.

Store object: store.get()

The store object contains key/value pairs, referred to as global variables, that specify variables or constants that can be used in multiple functions. Global variables can be added, edited, and deleted from the Code tab of the functions code editor. Functions can retrieve the value of a global variable, but cannot modify it.

To retrieve a value for a key, functions call store.get() and pass the key as the parameter. For more information, see Manage global variables.

For example, if you create a global variable with a key named date, a function would retrieve the value for date as follows:

store.get('date')

Sending an event to Tealium Collect

The following example shows how to send an event to the Tealium Collect HTTP API. The response interface of the Tealium Collect HTTP API represents the response to a request. The response model is the same as for the fetch API, except that the URL is not accessible in the result from the collect client.

Example

import {event, tealium} from 'tealium';

var newEvent = {‘key’: ‘value’};

tealium.sendCollectEvent(newEvent, 'newAccount', 'newProfile', 'datasourceId')
    .then(response => {
        if (!response.ok) {
            throw new Error(`Network response was not ok. Status code: ${response.status}.`);
        }

        console.log('Status code:', response.status);
        return response.text();
    })
    .then(data => console.log('Result:', data))
    .catch(error => console.error('Error:', error.message));


function buildURLSearchParams(params, data, parentKey) {
    if (data && typeof data === 'object' && !(data instanceof Date)) {
        Object.keys(data).forEach(key => {
            buildURLSearchParams(params, data[key], parentKey ? `${parentKey}[${key}]` : key);
        });
    } else {
        const value = data == null ? '' : data;

        params.append(parentKey, value);
    }
}