feat(mobx): add drafts and state context

src/mobx/stores/Auth.ts

@@ -0,0 +1,70 @@
+import { makeAutoObservable } from "mobx";
+import { Session } from "revolt-api/types/Auth";
+import { Nullable } from "revolt.js/dist/util/null";
+
+import Persistent from "../Persistent";
+import { deleteKey } from "../objectUtil";
+
+interface Data {
+    sessions: Record<string, Session>;
+    current?: string;
+}
+
+/**
+ * Handles account authentication, managing multiple
+ * accounts and their sessions.
+ */
+export default class Auth implements Persistent<Data> {
+    private sessions: Record<string, Session>;
+    private current: Nullable<string>;
+
+    /**
+     * Construct new Auth store.
+     */
+    constructor() {
+        this.sessions = {};
+        this.current = null;
+        makeAutoObservable(this);
+    }
+
+    // eslint-disable-next-line require-jsdoc
+    toJSON() {
+        return {
+            sessions: this.sessions,
+            current: this.current,
+        };
+    }
+
+    // eslint-disable-next-line require-jsdoc
+    hydrate(data: Data) {
+        this.sessions = data.sessions;
+        if (data.current && this.sessions[data.current]) {
+            this.current = data.current;
+        }
+    }
+
+    /**
+     * Add a new session to the auth manager.
+     * @param session Session
+     */
+    setSession(session: Session) {
+        this.sessions = {
+            ...this.sessions,
+            [session.user_id]: session,
+        };
+
+        this.current = session.user_id;
+    }
+
+    /**
+     * Remove existing session by user ID.
+     * @param user_id User ID tied to session
+     */
+    removeSession(user_id: string) {
+        this.sessions = deleteKey(this.sessions, user_id);
+
+        if (user_id == this.current) {
+            this.current = null;
+        }
+    }
+}