Use Immutable Record for accounts in Redux state (#26559)

app/javascript/mastodon/models/relationship.ts

@@ -0,0 +1,29 @@
+import type { RecordOf } from 'immutable';
+import { Record } from 'immutable';
+
+import type { ApiRelationshipJSON } from 'mastodon/api_types/relationships';
+
+type RelationshipShape = Required<ApiRelationshipJSON>; // no changes from server shape
+export type Relationship = RecordOf<RelationshipShape>;
+
+const RelationshipFactory = Record<RelationshipShape>({
+  blocked_by: false,
+  blocking: false,
+  domain_blocking: false,
+  endorsed: false,
+  followed_by: false,
+  following: false,
+  id: '',
+  languages: null,
+  muting_notifications: false,
+  muting: false,
+  note: '',
+  notifying: false,
+  requested_by: false,
+  requested: false,
+  showing_reblogs: false,
+});
+
+export function createRelationship(attributes: Partial<RelationshipShape>) {
+  return RelationshipFactory(attributes);
+}