Package Exports

@commercengine/js
@commercengine/js/cdn
@commercengine/js/package.json

Readme

@commercengine/js

Embed Commerce Engine checkout in any website.

Installation

CDN (Recommended)

<script src="https://js.commercengine.com/v1.js" async></script>

npm

npm install @commercengine/js

Quick Start

<script src="https://js.commercengine.com/v1.js" async></script>
<script>
  window.Commercengine.onLoad = async () => {
    const checkout = await Commercengine.init({
      storeId: "store_xxx",
      apiKey: "ak_xxx",
    });

    document.getElementById("cart-btn").onclick = () => checkout.openCart();
  };
</script>

Configuration

CheckoutConfig

interface CheckoutConfig {
  // === Credentials (required) ===
  storeId: string;              // Your Commerce Engine Store ID
  apiKey: string;               // Your Commerce Engine API Key

  // === Development ===
  url?: string;                 // Direct checkout URL (local dev only)
                                // If provided, storeId/apiKey are optional

  // === Theme ===
  theme?: "light" | "dark" | "system";  // Default: "system"

  // === Appearance ===
  appearance?: {
    zIndex?: number;            // Overlay z-index. Default: 99999
  };

  // === Authentication ===
  authMode?: "managed" | "provided";  // Default: "managed"
  accessToken?: string;         // Initial access token (if user logged in)
  refreshToken?: string;        // Initial refresh token

  // === Quick Buy (add item on init) ===
  quickBuy?: {
    productId: string;          // Product ID (required)
    variantId: string | null;   // Variant ID (required, null for non-variant)
    quantity?: number;          // Default: 1
  };
  sessionMode?: "continue-existing" | "force-new";  // Default: "continue-existing"
  autoDetectQuickBuy?: boolean; // Auto-detect from parent URL. Default: false

  // === Callbacks ===
  onReady?: () => void;
  onOpen?: () => void;
  onClose?: () => void;
  onComplete?: (order: OrderData) => void;
  onCartUpdate?: (cart: CartData) => void;
  onAuthChange?: (auth: AuthChangeData) => void;
}

Example: Full Configuration

const checkout = await Commercengine.init({
  storeId: "store_xxx",
  apiKey: "ak_xxx",
  theme: "dark",
  appearance: {
    zIndex: 100000,
  },
  accessToken: userSession?.accessToken,
  refreshToken: userSession?.refreshToken,
  onReady: () => {
    console.log("Checkout loaded");
  },
  onComplete: (order) => {
    window.location.href = `/thank-you?order=${order.orderNumber}`;
  },
  onCartUpdate: (cart) => {
    updateCartBadge(cart.count);
  },
  onAuthChange: ({ type, accessToken }) => {
    if (type === "login") {
      // User logged in via checkout - sync to your auth system
      saveUserSession(accessToken);
    } else if (type === "logout") {
      clearUserSession();
    }
  },
});

Methods

`openCart()`

Open the cart drawer.

checkout.openCart();

`openCheckout()`

Open checkout directly, bypassing cart. Use for "Buy Now" flows.

checkout.openCheckout();

`close()`

Close the checkout overlay.

checkout.close();

`updateTokens(accessToken, refreshToken?)`

Sync authentication state from parent site. Call when user logs in/out on your site.

// When user logs in on your site
checkout.updateTokens(session.accessToken, session.refreshToken);

// When user logs out
checkout.updateTokens("", "");

`addToCart(productId, variantId, quantity?)`

Add an item to cart and open the cart drawer. This is the canonical implementation of "quick buy" functionality.

// Add a product (non-variant)
checkout.addToCart("prod_123", null, 1);

// Add a product variant
checkout.addToCart("prod_123", "var_456", 2);

// Quantity defaults to 1
checkout.addToCart("prod_123", "var_456");

Parameters:

productId (string, required) - Product ID
variantId (string | null, required) - Variant ID, or null for non-variant products
quantity (number, optional) - Quantity to add, defaults to 1

Behavior:

Adds item to cart and automatically opens the cart drawer
If item already in cart: adds to existing quantity
If item not in cart: adds new item
If no cart exists: creates cart with the item

`getCart()`

Get current cart state.

const cart = checkout.getCart();
console.log(cart.count, cart.total, cart.currency);

`destroy()`

Remove checkout iframe and cleanup event listeners.

checkout.destroy();

Properties

Property	Type	Description
`ready`	`boolean`	Whether checkout is initialized and ready
`open`	`boolean`	Whether checkout overlay is currently visible

Events

Subscribe via callbacks (in config) or the event emitter.

Event Types

Event	Callback	Data	Description
`ready`	`onReady`	-	Checkout iframe loaded
`open`	`onOpen`	-	Drawer opened
`close`	`onClose`	-	All drawers closed
`complete`	`onComplete`	`OrderData`	Order placed successfully
`cart:updated`	`onCartUpdate`	`CartData`	Cart state changed
`auth:change`	`onAuthChange`	`AuthChangeData`	Auth state changed

Event Data Types

interface OrderData {
  id: string;           // Order ID
  orderNumber: string;  // Human-readable order number
}

interface CartData {
  count: number;        // Number of items
  total: number;        // Subtotal amount
  currency: string;     // Currency code (e.g., "USD", "INR")
}

interface AuthChangeData {
  type: "login" | "logout" | "refresh";
  accessToken?: string;   // New token (on login/refresh)
  refreshToken?: string;  // New refresh token
}

Event Emitter API

// Subscribe
checkout.on("cart:updated", (cart) => {
  console.log("Cart:", cart.count, cart.total);
});

// Subscribe once
checkout.once("complete", (order) => {
  console.log("Order:", order.orderNumber);
});

// Unsubscribe
const handler = (cart) => console.log(cart);
checkout.on("cart:updated", handler);
checkout.off("cart:updated", handler);

Authentication Flow

Scenario 1: User Not Logged In

User will be prompted to login within checkout (WhatsApp, Phone, or Email OTP).

const checkout = await Commercengine.init({
  storeId: "store_xxx",
  apiKey: "ak_xxx",
  onAuthChange: ({ type, accessToken, refreshToken }) => {
    if (type === "login") {
      // Save tokens to your auth system
      saveSession({ accessToken, refreshToken });
    }
  },
});

Scenario 2: User Already Logged In

Pass tokens to skip login screen.

const checkout = await Commercengine.init({
  storeId: "store_xxx",
  apiKey: "ak_xxx",
  accessToken: currentSession.accessToken,
  refreshToken: currentSession.refreshToken,
});

Scenario 3: Sync Auth Changes

When user logs in/out on your site, sync to checkout.

// User logs in on your site
myAuth.onLogin((session) => {
  checkout.updateTokens(session.accessToken, session.refreshToken);
});

// User logs out on your site
myAuth.onLogout(() => {
  checkout.updateTokens("", "");
});

TypeScript

All types are exported:

import {
  Commercengine,
  Checkout,
  type CheckoutConfig,
  type CheckoutEventType,
  type CartData,
  type OrderData,
  type AuthChangeData,
} from "@commercengine/js";

URL Parameters (Advanced)

For direct iframe integration without the SDK, checkout accepts these URL parameters:

Parameter	Description	Example
`store_id`	Store ID	`store_xxx`
`api_key`	API Key	`ak_xxx`
`mode`	Deployment mode	`iframe`
`parent_origin`	Parent origin for postMessage	`https://brand.com`
`theme`	Theme preference	`light`, `dark`
`token`	Access token	JWT string
`refresh_token`	Refresh token	JWT string
`auth_mode`	Auth management	`provided`, `managed`
`product_id`	Quick buy product	Product ID
`variant_id`	Quick buy variant	Variant ID
`qty`	Quick buy quantity	`1`
`session_mode`	Session behavior	`continue-existing`, `force-new`

Auth Modes

managed (default): Checkout manages token lifecycle with auto-refresh
provided: Parent manages tokens. Checkout uses in-memory only, syncs changes via events

Session Modes

continue-existing (default): Add quick-buy item to existing cart
force-new: Delete existing cart and start fresh with only the quick-buy item

Note: When quick buy params are provided (via config or auto-detected), the cart drawer automatically opens once checkout is ready.

Auto-Detect Quick Buy

For ad-driven traffic, enable autoDetectQuickBuy to automatically parse quick buy params from the parent page URL:

// Ad link: https://brand.com?product_id=prod_123&variant_id=var_456&qty=2

const checkout = await Commercengine.init({
  storeId: "store_xxx",
  apiKey: "ak_xxx",
  autoDetectQuickBuy: true,  // Reads product_id, variant_id, qty from parent URL
});

This allows embedded checkout to handle ad clicks natively without custom URL parsing.

URL Cleanup: When quick buy params are detected, they are automatically removed from the browser URL (using replaceState) to prevent duplicate adds on page refresh.