RivetKit provides several TypeScript helper types to make it easier to work with actors in a type-safe way.

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Context Types

When working with actors, you often need to access the context object. RivetKit provides helper types to extract the context types from actor definitions.

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ActorContextOf<ActorDefinition>

Extracts the full actor context type from a actor definition. This is the type of the context object (c) available in lifecycle hooks such as onCreate, onStart, etc.

import { actor, ActorContextOf } from "@rivetkit/actor";

const chatRoom = actor({
  state: { messages: [] },
  actions: {
    sendMessage: (c, message) => {
      // ...
    }
  }
});

// Extract the chat room context type
type ChatRoomContext = ActorContextOf<typeof chatRoom>;

// Now you can use this type elsewhere
function processChatRoomContext(context: ChatRoomContext) {
  // Access context properties with full type safety
  console.log(context.state.messages);
  context.broadcast("newEvent", { type: "system" });
}

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ActionContextOf<ActorDefinition>

Extracts the action context type from a actor definition. This is the type of the context object (c) available in action handlers.

import { actor, ActionContextOf } from "@rivetkit/actor";

const counter = actor({
  state: { count: 0 },
  actions: {
    increment: (c) => {
      c.state.count++;
      return c.state.count;
    }
  }
});

// Extract the action context type
type CounterActionContext = ActionContextOf<typeof counter>;

// Use in other functions that need to work with the action context
function processCounterAction(context: CounterActionContext) {
  // Access context with full type safety
  context.state.count++;
}