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import { BroadcastChannel, BroadcastChannelOptions } from "./broadcast.ts";import { Receiver } from "./channel.ts";import { ChannelPipeOptions } from "./pipe.ts";
export const otherTopics: unique symbol = Symbol("other");
export type SubscribeOptions =  & BroadcastChannelOptions  & Omit<ChannelPipeOptions, "signal">;
export type SubscribeReturnType<TMsg, TObj> =  & { [r in keyof TObj]: Receiver<TMsg> }  & { [otherTopics]: Receiver<TMsg> };
export function subscribe<TMsg, TObj>(  fn: (_: TMsg) => string | symbol | number,  topics: (keyof TObj)[],  pipeOpts?: SubscribeOptions,) {  return (ch: Receiver<TMsg>): SubscribeReturnType<TMsg, TObj> => {    const { bufferSize: tmpBufferSize, sendMode, ...commonOpts } = pipeOpts ??      {};
    const bufferSize = tmpBufferSize ?? ch.bufferSize;
    const broadcastCh = BroadcastChannel.from(ch, fn, {      ...commonOpts,      sendMode,    });
    const [otherSub] = broadcastCh.subscribeFn(      (topic) => !(topics as unknown[]).includes(topic),      { ...commonOpts, bufferSize },    );
    const topicSubs = Object.fromEntries(      topics.map((topic) => {        return [          topic,          broadcastCh.subscribe(topic, { ...commonOpts, bufferSize })[0],        ];      }),    ) as { [r in keyof TObj]: Receiver<TMsg> };
    return { [otherTopics]: otherSub, ...topicSubs };  };}