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| 1 | +import NDK, { |
| 2 | + type NDKConstructorParams, |
| 3 | + NDKEvent, |
| 4 | + type NDKFilter, |
| 5 | + type NDKRelay, |
| 6 | + type NDKRelaySet, |
| 7 | + type NDKSubscriptionOptions, |
| 8 | +} from "@nostr-dev-kit/ndk"; |
| 9 | +import { onDestroy } from "svelte"; |
| 10 | + |
| 11 | +type ClassWithConvertFunction<T extends NDKEvent> = { |
| 12 | + from: (event: NDKEvent) => T | undefined; |
| 13 | +}; |
| 14 | + |
| 15 | +type NDKSubscribeOptions = NDKSubscriptionOptions & { |
| 16 | + autoStart?: boolean; |
| 17 | + repostsFilters?: NDKFilter[]; |
| 18 | + unrefUnsubscribeTimeout?: number; |
| 19 | + relaySet?: NDKRelaySet; |
| 20 | + skipDeleted?: boolean; |
| 21 | + onEose?: () => void; |
| 22 | + onEvent?: (event: NDKEvent, relay?: NDKRelay) => void; |
| 23 | +}; |
| 24 | + |
| 25 | +type Actions = { |
| 26 | + unsubscribe?: () => void; |
| 27 | +}; |
| 28 | + |
| 29 | +class NDKSvelte extends NDK { |
| 30 | + constructor(opts?: NDKConstructorParams) { |
| 31 | + super(opts); |
| 32 | + } |
| 33 | + |
| 34 | + /** |
| 35 | + * Subscribes to NDK events and returns a reactive list of events. |
| 36 | + * Automatically cleans up the subscription when no longer needed. |
| 37 | + */ |
| 38 | + public $subscribe = <T extends NDKEvent>( |
| 39 | + filters: NDKFilter[], |
| 40 | + opts?: NDKSubscribeOptions, |
| 41 | + klass?: ClassWithConvertFunction<T> |
| 42 | + ) => { |
| 43 | + // A reactive list for the events |
| 44 | + const eventList = $state<T[] & Actions>([]); |
| 45 | + const eventMap = new Map<string, T>(); // Map for deduplication |
| 46 | + |
| 47 | + // Process an incoming event |
| 48 | + const processEvent = (event: NDKEvent) => { |
| 49 | + let e = event; |
| 50 | + |
| 51 | + // Convert the event to a specific class if provided |
| 52 | + if (klass) { |
| 53 | + const convertedEvent = klass.from(event); |
| 54 | + if (!convertedEvent) return; |
| 55 | + e = convertedEvent; |
| 56 | + e.relay = event.relay; |
| 57 | + } |
| 58 | + |
| 59 | + const dedupKey = e.deduplicationKey(); |
| 60 | + |
| 61 | + // Avoid duplicate or older events |
| 62 | + if (eventMap.has(dedupKey)) { |
| 63 | + const existingEvent = eventMap.get(dedupKey)!; |
| 64 | + if (existingEvent.created_at! >= e.created_at!) return; |
| 65 | + } |
| 66 | + |
| 67 | + eventMap.set(dedupKey, e as T); |
| 68 | + |
| 69 | + // Update the reactive event list inserting the event in the right position according to the created_at timestamp |
| 70 | + const pos = eventList.findIndex(event => event.created_at! < e.created_at!); |
| 71 | + eventList.splice(pos, 0, e as T); |
| 72 | + }; |
| 73 | + |
| 74 | + // Create the subscription |
| 75 | + const subscription = this.subscribe( |
| 76 | + Array.isArray(filters) ? filters : [filters], |
| 77 | + opts, |
| 78 | + opts?.relaySet, |
| 79 | + false |
| 80 | + ); |
| 81 | + |
| 82 | + // Handle incoming events |
| 83 | + subscription.on("event", (event, relay) => { |
| 84 | + processEvent(event); |
| 85 | + if (opts?.onEvent) opts.onEvent(event, relay); |
| 86 | + }); |
| 87 | + |
| 88 | + // Handle EOSE |
| 89 | + subscription.on("eose", () => { |
| 90 | + if (opts?.onEose) opts.onEose(); |
| 91 | + }); |
| 92 | + |
| 93 | + subscription.start(); |
| 94 | + |
| 95 | + // Cleanup when the component or context is destroyed |
| 96 | + onDestroy(() => { |
| 97 | + subscription.stop(); |
| 98 | + }); |
| 99 | + |
| 100 | + eventList.unsubscribe = () => subscription.stop(); |
| 101 | + |
| 102 | + return eventList; |
| 103 | + } |
| 104 | +} |
| 105 | + |
| 106 | +export default NDKSvelte; |
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