Enhance form configuration to support project ID

Author: lpssformspree

packages/formspree-ajax/src/form.ts

@@ -1,4 +1,5 @@
 import {
+  createClient,
   getDefaultClient,
   isSubmissionError,
   appendExtraData,
@@ -421,7 +422,9 @@ export const initForm = <T extends FieldValues = FieldValues>(
   const form = getFormElement(config.formElement);
   const formKey = config.formId;
   const endpoint = config.origin ?? DEFAULT_ENDPOINT;
-  const client: Client = getDefaultClient();
+  const client: Client = config.projectId
+    ? createClient({ project: config.projectId })
+    : getDefaultClient();
 
   const context: FormContext<T> = {
     form,

packages/formspree-ajax/src/types.ts

@@ -116,7 +116,11 @@ export type MessageType = 'success' | 'error';
  * @template T - The type of field values for the form, defaults to FieldValues.
  */
 export interface FormConfig<T extends FieldValues = FieldValues> {
-  // TODO: add a project id
+  /**
+   * The Formspree project ID. When provided, submissions are sent to
+   * `/p/{projectId}/f/{formId}` instead of `/f/{formId}`.
+   */
+  projectId?: string;
 
   /**
    * The form element to attach to, either as an HTMLFormElement or a CSS selector string.