/**
 * part of Hachette
 * Facilitate listening to events
 *
 * Copyright (C) 2021 Wojtek Kosior
 * Redistribution terms are gathered in the `copyright' file.
 */

const make = (value=undefined) => ({value, listeners: new Set()});
const subscribe = (observable, cb) => observable.listeners.add(cb);
const unsubscribe = (observable, cb) => observable.listeners.delete(cb);

const silent_set = (observable, value) => observable.value = value;
const broadcast = (observable, ...values) =>
      observable.listeners.forEach(cb => cb(...values));

function set(observable, value)
{
    const old_value = observable.value;
    silent_set(observable, value);
    broadcast(observable, value, old_value);
}

const observables = {make, subscribe, unsubscribe, broadcast, silent_set, set};

/*
 * EXPORTS_START
 * EXPORT observables
 * EXPORTS_END
 */
tion>
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<div class='path'>path: <a href='/guix/log/?id=9579f37bcc1c834bda4ae6233685e8607d9a1169'>root</a>/<a href='/guix/log/etc?id=9579f37bcc1c834bda4ae6233685e8607d9a1169'>etc</a>/<a href='/guix/log/etc/init.d?id=9579f37bcc1c834bda4ae6233685e8607d9a1169'>init.d</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/etc/init.d?id=9579f37bcc1c834bda4ae6233685e8607d9a1169&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2024-06-26 22:59:55 +0200'>2024-06-26</span></td><td><a href='/guix/commit/etc/init.d?id=d11b96eb5493231a5a35045505ff8ae8aa746b8e'>etc: Add explicit ‘--substitute-urls’ in guix-daemon service files.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>