feat(arrays): Add arrays payload support for transactional email api (#13)

Co-authored-by: Dan <dan@loops.so>

Author: fantactuka

README.md

@@ -621,17 +621,17 @@ Send a transactional email to a contact. [Learn about sending transactional emai
 
 #### Parameters
 
-| Name                        | Type     | Required | Notes                                                                                                                                                                                            |
-| --------------------------- | -------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
-| `transactionalId`           | string   | Yes      | The ID of the transactional email to send.                                                                                                                                                       |
-| `email`                     | string   | Yes      | The email address of the recipient.                                                                                                                                                              |
-| `addToAudience`             | boolean  | No       | If `true`, a contact will be created in your audience using the `email` value (if a matching contact doesn’t already exist).                                                                     |
-| `dataVariables`             | object   | No       | An object containing data as defined by the data variables added to the transactional email template.<br />Values can be of type `string` or `number`.                                           |
-| `attachments`               | object[] | No       | A list of attachments objects.<br />**Please note**: Attachments need to be enabled on your account before using them with the API. [Read more](https://loops.so/docs/transactional/attachments) |
-| `attachments[].filename`    | string   | No       | The name of the file, shown in email clients.                                                                                                                                                    |
-| `attachments[].contentType` | string   | No       | The MIME type of the file.                                                                                                                                                                       |
-| `attachments[].data`        | string   | No       | The base64-encoded content of the file.                                                                                                                                                          |
-| `headers`                   | object   | No       | Additional headers to send with the request.                                                                                                                                                     |
+| Name                        | Type     | Required | Notes                                                                                                                                                                                                         |
+| --------------------------- | -------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `transactionalId`           | string   | Yes      | The ID of the transactional email to send.                                                                                                                                                                    |
+| `email`                     | string   | Yes      | The email address of the recipient.                                                                                                                                                                           |
+| `addToAudience`             | boolean  | No       | If `true`, a contact will be created in your audience using the `email` value (if a matching contact doesn’t already exist).                                                                                  |
+| `dataVariables`             | object   | No       | An object containing data as defined by the data variables added to the transactional email template.<br />Values can be of type `string`, `number`, or an array of objects with `string` or `number` values. |
+| `attachments`               | object[] | No       | A list of attachments objects.<br />**Please note**: Attachments need to be enabled on your account before using them with the API. [Read more](https://loops.so/docs/transactional/attachments)              |
+| `attachments[].filename`    | string   | No       | The name of the file, shown in email clients.                                                                                                                                                                 |
+| `attachments[].contentType` | string   | No       | The MIME type of the file.                                                                                                                                                                                    |
+| `attachments[].data`        | string   | No       | The base64-encoded content of the file.                                                                                                                                                                       |
+| `headers`                   | object   | No       | Additional headers to send with the request.                                                                                                                                                                  |
 
 #### Examples
 
@@ -770,7 +770,8 @@ const resp = await loops.getTransactionalEmails({ perPage: 15 });
 
 ## Version history
 
-- `v6.1.0` (Jan 29, 2026) - Added `rawBody` to `APIError` in the case no JSON is received from the server (thanks to [@leipert](https://github.com/leipert)).
+- `v6.2.0` (Feb 9, 2026) - Support for the new arrays feature in sendTransactionalEmail.
+- `v6.1.2` (Jan 29, 2026) - Added `rawBody` to `APIError` in the case no JSON is received from the server (thanks to [@leipert](https://github.com/leipert)).
 - `v6.0.1` (Oct 15, 2025) - Added `optInStatus` to contact object in [`findContact()`](#findcontact) for the new double opt-in feature.
 - `v6.0.0` (Aug 22, 2025) - [`createContact()`](#createcontact) and [`updateContact()`](#updatecontact) now have a single object parameter instead of named parameters (breaking change). This allows support for using either `email` or `userId` when updating contacts.
 - `v5.0.1` (May 13, 2025) - Added a `headers` parameter for [`sendEvent()`](#sendevent) and [`sendTransactionalEmail()`](#sendtransactionalemail), enabling support for the `Idempotency-Key` header.

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "loops",
-  "version": "6.1.2",
+  "version": "6.2.0",
   "author": "Dan Rowden <dan@loops.so>",
   "license": "MIT",
   "main": "./dist/index.cjs",

package.json

@@ -499,7 +499,10 @@ describe("LoopsClient", () => {
         email: "test@example.com",
         dataVariables: {
           name: "John",
-          product: "Widgets",
+          products: [
+            { name: "Widget", price: 29.99 },
+            { name: "Gadget", price: 49.99 },
+          ],
         },
       };
       const mockResponse = { success: true };

src/__tests__/LoopsClient.test.ts

@@ -111,7 +111,10 @@ type EventProperties = Record<string, string | number | boolean>;
 
 type MailingLists = Record<string, boolean>;
 
-type TransactionalVariables = Record<string, string | number>;
+type TransactionalVariables = Record<
+  string,
+  string | number | Array<Record<string, string | number>>
+>;
 
 interface TransactionalAttachment {
   /**