Strict InjectionKey Symbol Contracts for Hierarchical State Provision

import { provide, inject, InjectionKey, ref, Ref } from 'vue';
 
interface UserContext {
  userId: Ref<string>;
  permissions: Ref<string[]>;
  revokeAccess: () => void;
}
 
export const USER_CONTEXT_KEY: InjectionKey<UserContext> = Symbol('UserContextKey');
 
export function useProvideUserContext(id: string) {  const userId = ref(id);
  const permissions = ref(['read', 'write']);
  const revokeAccess = () => { permissions.value = []; };
 
  const context: UserContext = { userId, permissions, revokeAccess };
  provide(USER_CONTEXT_KEY, context);
  return context;
}
 
export function useInjectUserContext(): UserContext {
  const context = inject(USER_CONTEXT_KEY);
  if (!context) {
    throw new Error('UserContext injection attempted outside provider subtree');
  }
  return context;
};