50 lines
1.2 KiB
TypeScript
50 lines
1.2 KiB
TypeScript
// Copyright: Ankitects Pty Ltd and contributors
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// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
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import type { Writable, Subscriber, Unsubscriber, Updater } from "svelte/store";
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import { noop } from "../lib/functional";
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export interface NodeStore<T extends Node> extends Writable<T> {
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setUnprocessed(node: T): void;
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}
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export function nodeStore<T extends Node>(
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node?: T,
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preprocess: (node: T) => void = noop,
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): NodeStore<T> {
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const subscribers: Set<Subscriber<T>> = new Set();
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function setUnprocessed(newNode: T): void {
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if (!node || !node.isEqualNode(newNode)) {
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node = newNode;
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for (const subscriber of subscribers) {
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subscriber(node);
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}
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}
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}
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function set(newNode: T): void {
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preprocess(newNode);
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setUnprocessed(newNode);
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}
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function update(fn: Updater<T>): void {
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set(fn(node!));
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}
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function subscribe(subscriber: Subscriber<T>): Unsubscriber {
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subscribers.add(subscriber);
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if (node) {
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subscriber(node);
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}
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return () => subscribers.delete(subscriber);
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}
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return { set, setUnprocessed, update, subscribe };
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}
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export default nodeStore;
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