nip77: adds wrapper for negentropy and fallback for yieldThread MessageChannel

nip77.ts

@@ -0,0 +1,21 @@
+import { Filter } from './filter.ts'
+import { AbstractRelay } from './relay.ts'
+
+function sendNegentropyToRelay(open: boolean, relay: AbstractRelay, msg: string, filters: Filter[], subscriptionId?: any): void {
+  const subId = subscriptionId || Math.random().toString(36).slice(2, 10)
+  const parts: any[] = [open ? 'NEG-OPEN' : 'NEG-MSG', subId, ...filters, msg]
+  relay.send(JSON.stringify(parts))
+}
+
+export function sendNegentropyMessage(relay: AbstractRelay, msg: string, filters: Filter[], subscriptionId?: any): void {
+  sendNegentropyToRelay(false, relay, msg, filters, subscriptionId)
+}
+
+export function openNegentropyWithMessage(relay: AbstractRelay, msg: string, filters: Filter[], subscriptionId?: any): void {
+  sendNegentropyToRelay(true, relay, msg, filters, subscriptionId)
+}
+
+export function closeNegentropy(relay: AbstractRelay, subscriptionId: string): void {
+  const request = '["NEG-CLOSE","' + subscriptionId + '"]'
+  relay.send(request)
+}