Preselect plan on mount

ee/app/assets/javascripts/subscriptions/buy_minutes/components/checkout.vue

 <script>
+import updateState from 'ee/subscriptions/graphql/mutations/update_state.mutation.graphql';
+import { GENERAL_ERROR_MESSAGE } from 'ee/vue_shared/purchase_flow/constants';
+import createFlash from '~/flash';
 import { s__ } from '~/locale';
 import AddonPurchaseDetails from './checkout/addon_purchase_details.vue';
 import BillingAddress from './checkout/billing_address.vue';
@@ -13,6 +16,23 @@ export default {
       required: true,
     },
   },
+  mounted() {
+    this.updateSelectedPlanId(this.plan.id);
+  },
+  methods: {
+    updateSelectedPlanId(planId) {
+      this.$apollo
+        .mutate({
+          mutation: updateState,
+          variables: {
+            input: { selectedPlanId: planId },
+          },
+        })
+        .catch((error) => {
+          createFlash({ message: GENERAL_ERROR_MESSAGE, error, captureError: true });
+        });
+    },
+  },
   i18n: {
     checkout: s__('Checkout|Checkout'),
   },

ee/app/assets/javascripts/subscriptions/buy_minutes/components/checkout/confirm_order.vue

@@ -31,21 +31,8 @@ export default {
     confirmOrderParams: {
       query: stateQuery,
       update(data) {
-        const { customer } = data;
-
         return {
-          setup_for_company: data.isSetupForCompany,
           selected_group: data.subscription.namespaceId,
-          new_user: data.isNewUser,
-          customer: {
-            country: customer.country,
-            address_1: customer.address1,
-            address_2: customer.address2,
-            city: customer.city,
-            state: customer.state,
-            zip_code: customer.zipCode,
-            company: customer.company,
-          },
           subscription: {
             plan_id: data.selectedPlanId,
             payment_method_id: data.paymentMethod.id,

ee/app/assets/javascripts/subscriptions/buy_minutes/utils.js

@@ -11,7 +11,7 @@ function arrayToGraphqlArray(arr, typename) {
 }
 
 export function writeInitialDataToApolloCache(apolloProvider, dataset) {
-  const { groupData, namespaceId, planId = null } = dataset;
+  const { groupData, namespaceId } = dataset;
   // eslint-disable-next-line @gitlab/require-i18n-strings
   const namespaces = arrayToGraphqlArray(JSON.parse(groupData), 'Namespace');
 
@@ -21,7 +21,7 @@ export function writeInitialDataToApolloCache(apolloProvider, dataset) {
       isNewUser: false,
       fullName: null,
       isSetupForCompany: false,
-      selectedPlanId: planId,
+      selectedPlanId: null,
       namespaces,
       subscription: {
         quantity: 1,