Last active
April 19, 2020 21:24
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Patches Meteor.subscribe and Tracker.autorun to stop when a Svelte component is destroyed. Also supports await block for subscriptions.
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import { current_component } from 'svelte/internal'; | |
_autorun = Tracker.autorun; | |
Tracker.autorun = function autorun() { | |
const computation = _autorun.apply(this, arguments); | |
if (current_component) { | |
current_component.$$.on_destroy.push(computation.stop.bind(computation)); | |
} | |
return computation; | |
}; | |
_subscribe = Meteor.subscribe; | |
Meteor.subscribe = function subscribe(name) { | |
const params = Array.from(arguments); | |
let callbacks = Object.create(null); | |
if (params.length > 1) { | |
// Preserve existing callbacks. | |
// Last arg may be specified as a function, or as an object | |
const last = params[params.length - 1]; | |
if (typeof last === 'function') { | |
callbacks.onReady = params.pop(); | |
} else if (last && [last.onReady, last.onError, last.onStop].some(f => typeof f === "function")) { | |
callbacks = params.pop(); | |
} | |
} | |
params.push(callbacks); | |
let subscription; | |
// Collect callbacks to call when subscription is ready or has errored. | |
let readyCallbacks = []; | |
let errorCallbacks = []; | |
if (callbacks.onReady) { | |
readyCallbacks.push(callbacks.onReady); | |
} | |
if (callbacks.onError) { | |
errorCallbacks.push(callbacks.onError); | |
} | |
callbacks.onReady = () => { | |
readyCallbacks.forEach(fn => fn(subscription)); | |
readyCallbacks.length = 0; | |
}; | |
callbacks.onError = (err) => { | |
errorCallbacks.forEach(fn => fn(err)); | |
errorCallbacks.length = 0; | |
}; | |
subscription = _subscribe.apply(this, params); | |
if (current_component) { | |
current_component.$$.on_destroy.push(subscription.stop.bind(subscription)); | |
} | |
subscription.then = (fn, err) => { | |
readyCallbacks.push(fn); | |
err && errorCallbacks.push(err); | |
}; | |
return subscription; | |
}; |
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