Custom Conditions

When the built-in condition types are not enough, custom conditions let you write your own targeting logic. You can evaluate any JavaScript expression, or check for specific cookies. If the condition returns true, the visitor matches. If it returns false, they do not.

1. The JavaScript condition's code field: paste the lines that go inside the braces of the examples below.
2. The Cookie condition's Cookie name and Cookie value fields.

Custom condition types

JavaScript condition

A JavaScript condition is a snippet of code that the snippet evaluates at runtime. The code must return a boolean value: true to match, false to not match. You have full access to the global window object, so you can read any variable, property, or function that your application has set on the page.

A vs B runs the field's contents as a function body (new Function(yourCode)()), which is why every example below ends in a return. The examples show that body inside its wrapper so the types line up; paste only the lines inside the braces into the condition field.

If you keep your site's globals in TypeScript, declare them once and every condition below is checked against the real shapes:

declare global {  interface Window {    userTier?: string    cart?: { total: number }    featureFlags?: { newCheckout?: boolean }  }}

Check a user property:

function condition(): boolean {  // Include only premium tier users  return window.userTier === 'premium'}

Check the cart value:

function condition(): boolean {  // Include visitors with cart value over $100  return typeof window.cart !== 'undefined' && window.cart.total > 100}

Check if a feature flag is active:

function condition(): boolean {  // Include visitors with a specific feature flag enabled  return window.featureFlags?.newCheckout === true}

Check scroll position:

function condition(): boolean {  // Include visitors who have scrolled at least 200px  return window.scrollY > 200}

Read a value from a data layer (many sites push structured data to window.dataLayer for tag managers like Google Tag Manager). There is no dedicated Data Layer condition type; a JavaScript condition reads it directly, since window.dataLayer is just a regular array on the page:

declare global {  interface Window {    dataLayer?: Record<string, unknown>[]  }}function condition(): boolean {  // Search the data layer from most recent entry to oldest, and match the  // first one that set userStatus  const layer = window.dataLayer ?? []  const entry = [...layer].reverse().find((e) => 'userStatus' in e)  return entry?.userStatus === 'loggedIn'}

A push your site code makes might look like this:

window.dataLayer = window.dataLayer || [];window.dataLayer.push({  event: 'pageLoaded',  userStatus: 'loggedIn',  pageCategory: 'checkout',  customerSegment: 'high-value'});

Cookie condition

Cookie conditions check whether a specific browser cookie exists, and optionally whether its value matches a string you give. Use it to target visitors who have a cookie your application set: a session cookie, an auth cookie, or a custom preference cookie.

In the Audience Builder (the drag-and-drop screen where you build a targeting rule from conditions), add a condition of type Cookie. Then enter the cookie name and, optionally, a value to match against.

Cookie condition examples:

Check if an auth cookie exists (any value)  Cookie name: auth_token  Operator:    ExistsCheck if a preference cookie has a specific value  Cookie name: ui_theme  Operator:    Equals  Value:       darkExclude visitors with an opt-out cookie  Cookie name: analytics_optout  Operator:    Does not exist

Combining custom conditions

Custom conditions can be mixed freely with built-in conditions in the Audience Builder. For example, you might combine a device condition (Mobile) with a custom JavaScript condition (user is logged in) to target logged-in mobile users.

Remember that conditions within an audience are combined with AND logic by default: the visitor must satisfy all conditions. If you add a group, conditions within the group can use OR logic.

Custom Attribute condition (Feature Flags)

Feature Flag projects support a Custom Attribute condition type. It targets users based on properties your own code passes to the SDK during flag evaluation. Unlike JavaScript or cookie conditions, custom attributes work in both client-side and server-side SDKs.

To add a Custom Attribute condition, first pick an attribute from the registered list (configured in Audiences > Attributes). Then choose an operator and enter a comparison value. The available operators depend on the attribute's type:

• String: equals, contains, starts with, regex, in list, and more
• Number: equals, greater than, less than, and more
• Boolean: equals true or false
• JSON: contains, exists

Attributes ride on the evaluation context: the bundle of facts about a visitor (their id, plan, or any other property) that your code hands to the SDK when it asks for a flag. Attributes sit alongside the kind and key that identify the user:

import { AvsbClient } from '@avsbhq/browser'const client = new AvsbClient({  sdkKey: 'sdk_production_xxxxxxxxxxxxxxxx',  context: {    kind: 'user',    key: 'user_789',    plan: 'enterprise',    teamSize: 50,  },})// Those attributes are what audience conditions are evaluated against.// getFlag returns a Flag object, so read `.value` for the variation value.const showFeature = client.getFlag('new_dashboard', false).value