create-actor.ts

import { Actor, ActorConfig, ActorSubclass, Agent, HttpAgent, HttpAgentOptions } from "@dfinity/agent";
import { InterfaceFactory } from '@dfinity/candid/lib/cjs/idl';

export declare interface CreateActorOptions {
  /**
   * @see {@link Agent}
   */
  agent?: Agent;
  /**
   * @see {@link HttpAgentOptions}
   */
  agentOptions?: HttpAgentOptions;
  /**
   * @see {@link ActorConfig}
   */
  actorOptions?: ActorConfig;
}

export const createActor = <SERVICE>(canisterId: string, idlFactory: InterfaceFactory, options: CreateActorOptions = {}): ActorSubclass<SERVICE> => {
  const agent = options.agent || new HttpAgent({ ...options.agentOptions });

  if (options.agent && options.agentOptions) {
    console.warn(
      "Detected both agent and agentOptions passed to createActor. Ignoring agentOptions and proceeding with the provided agent."
    );
  }

  // Fetch root key for certificate validation during development
  if (process.env.DFX_NETWORK !== "ic") {
    agent.fetchRootKey().catch((err) => {
      console.warn(
        "Unable to fetch root key. Check to ensure that your local replica is running"
      );
      console.error(err);
    });
  }

  // Creates an actor with using the candid interface and the HttpAgent
  return Actor.createActor(idlFactory, {
    agent,
    canisterId,
    ...options.actorOptions,
  });
};