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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// TODO(petamoriken): enable prefer-primordials for node polyfills
// deno-lint-ignore-file prefer-primordials
import { ERR_INVALID_ARG_TYPE } from "ext:deno_node/internal/errors.ts";
import { validateFunction } from "ext:deno_node/internal/validators.mjs";
import { nextTick } from "node:process";
type Subscriber = (message: unknown, name?: string) => void;
export class Channel {
_subscribers: Subscriber[];
name: string;
constructor(name: string) {
this._subscribers = [];
this.name = name;
}
publish(message: unknown) {
for (const subscriber of this._subscribers) {
try {
subscriber(message, this.name);
} catch (err) {
nextTick(() => {
throw err;
});
}
}
}
subscribe(subscription: Subscriber) {
validateFunction(subscription, "subscription");
this._subscribers.push(subscription);
}
unsubscribe(subscription: Subscriber) {
if (!this._subscribers.includes(subscription)) {
return false;
}
this._subscribers.splice(this._subscribers.indexOf(subscription), 1);
return true;
}
get hasSubscribers() {
return this._subscribers.length > 0;
}
}
const channels: Record<string, Channel> = {};
export function channel(name: string) {
if (typeof name !== "string" && typeof name !== "symbol") {
throw new ERR_INVALID_ARG_TYPE("channel", ["string", "symbol"], name);
}
if (!Object.hasOwn(channels, name)) {
channels[name] = new Channel(name);
}
return channels[name];
}
export function hasSubscribers(name: string) {
if (!Object.hasOwn(channels, name)) {
return false;
}
return channels[name].hasSubscribers;
}
export function subscribe(name: string, subscription: Subscriber) {
const c = channel(name);
return c.subscribe(subscription);
}
export function unsubscribe(name: string, subscription: Subscriber) {
const c = channel(name);
return c.unsubscribe(subscription);
}
export default {
channel,
hasSubscribers,
subscribe,
unsubscribe,
Channel,
};
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