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/* eslint-disable import/prefer-default-export */
// eslint-disable-next-line no-restricted-imports
import { tick as svelteTick, onDestroy } from 'svelte';
// Unfortantely for TS to recognize that this can be awaited
// we need to leave `Promise<void | never>` otherwise TS hints
// will suggest removing the await.
// See @remarks for reason to disable `then`
type TickType = () => Omit<Promise<string>, 'then'> | Promise<void | never>;
type SafeTickCallback = (tick: TickType) => Promise<void | never>;
class DestroyedError extends Error {
constructor() {
super('component was destroyed before tick resolved.');
this.name = 'DestroyedError';
}
}
/**
* Provides a safer way to use svelte's tick helper.
*
* This prevents code that relies on tick() from running
* if the component is destroyed while the tick resolution
* is inflight.
*
* @remarks
* To avoid floating promises (promises with no return statements)
* it is safer to use the `async/await` syntax.
*
* If this is used with the `.then()` syntax without the promise
* being returned the DestroyedError will bubble up to sentry.
*
* @example
* ```ts
* const safeTick = makeSafeTick();
* onMount(async() => {
* await safeTick(async (tick) => {
* // Use tick normally
* await tick();
* // ...
* });
* });
* ```
*/
export const makeSafeTick = (): ((
callback: SafeTickCallback,
) => Promise<void | never>) => {
let destroyed = false;
onDestroy(() => {
destroyed = true;
});
return async (callback) => {
try {
await callback(async () => {
await svelteTick();
if (destroyed) throw new DestroyedError();
});
} catch (e) {
if (!(e instanceof DestroyedError)) throw e;
}
};
};
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