feat: temporarily copy decodeTokenPayload into this project from livekit-client

I should be able to get rid of this once this is merged:
livekit/client-sdk-js#1710

Author: 1egoman

packages/react/src/hooks/useSession.ts

@@ -10,13 +10,17 @@ import {
   TokenSourceFixed,
   TokenSourceFetchOptions,
   RoomConnectOptions,
+  TokenPayload,
+  RoomConfigurationObject,
 } from 'livekit-client';
 import { EventEmitter } from 'events';
 
 import { useMaybeRoomContext } from '../context';
 import { AgentState, useAgent, useAgentTimeoutIdStore } from './useAgent';
 import { TrackReference } from '@livekit/components-core';
 import { useLocalParticipant } from './useLocalParticipant';
+import { decodeJwt } from 'jose';
+import { RoomConfiguration } from '@livekit/protocol';
 
 /** @public */
 export enum SessionEvent {
@@ -153,6 +157,24 @@ type UseSessionCommonOptions = {
 type UseSessionConfigurableOptions = UseSessionCommonOptions & TokenSourceFetchOptions;
 type UseSessionFixedOptions = UseSessionCommonOptions;
 
+/** Given a LiveKit generated participant token, decodes and returns the associated {@link TokenPayload} data. */
+export function decodeTokenPayload(token: string) {
+  const payload = decodeJwt<Omit<TokenPayload, 'roomConfig'>>(token);
+
+  const { roomConfig, ...rest } = payload;
+
+  const mappedPayload: TokenPayload = {
+    ...rest,
+    roomConfig: payload.roomConfig
+      ? (RoomConfiguration.fromJson(
+          payload.roomConfig as Record<string, any>,
+        ) as RoomConfigurationObject)
+      : undefined,
+  };
+
+  return mappedPayload;
+}
+
 /**
  * A Session represents a manages connection to a Room which can contain Agents.
  * @public