Break down relay utils, replace removeNil with removeUndefined

packages/app/src/relays.ts

@@ -1,6 +1,15 @@
 import {writable, derived} from "svelte/store"
+import {
+  uniq,
+  removeUndefined,
+  prop,
+  indexBy,
+  batcher,
+  fetchJson,
+  postJson,
+  Maybe,
+} from "@welshman/lib"
 import {withGetter} from "@welshman/store"
-import {uniq, batcher, postJson} from "@welshman/lib"
 import {RelayProfile} from "@welshman/util"
 import {normalizeRelayUrl, displayRelayUrl, displayRelayProfile, isRelayUrl} from "@welshman/util"
 import {collection} from "@welshman/store"
@@ -8,36 +17,55 @@ import {appContext} from "./context.js"
 
 export const relays = withGetter(writable<RelayProfile[]>([]))
 
-export const fetchRelayProfiles = async (urls: string[]) => {
+export const fetchRelayProfileDirectly = async (url: string): Promise<Maybe<RelayProfile>> => {
+  try {
+    return fetchJson(url.replace(/^ws/, "http"), {
+      headers: {
+        Accept: "application/nostr+json",
+      },
+    })
+  } catch (e) {
+    // pass
+  }
+}
+
+export const fetchRelayProfilesDirectly = async (
+  urls: string[],
+): Promise<Map<string, RelayProfile>> =>
+  indexBy(
+    prop("url"),
+    removeUndefined(
+      await Promise.all(
+        urls.map(async url => {
+          const profile = await fetchRelayProfileDirectly(url)
+
+          if (profile) {
+            return {...profile, url}
+          }
+        }),
+      ),
+    ),
+  )
+
+export const fetchRelayProfilesUsingProxy = async (
+  proxy: string,
+  urls: string[],
+): Promise<Map<string, RelayProfile>> => {
   const profilesByUrl = new Map<string, RelayProfile>()
+  const res: any = await postJson(`${proxy}/relay/info`, {urls})
 
-  if (appContext.dufflepudUrl) {
-    const res: any = await postJson(`${appContext.dufflepudUrl}/relay/info`, {urls})
-
-    for (const {url, info} of res?.data || []) {
-      profilesByUrl.set(url, info)
-    }
-  } else {
-    await Promise.all(
-      urls.map(async url => {
-        try {
-          const res = await fetch(url.replace(/^ws/, "http"), {
-            headers: {
-              Accept: "application/nostr+json",
-            },
-          })
-
-          profilesByUrl.set(url, await res.json())
-        } catch (e) {
-          // pass
-        }
-      }),
-    )
+  for (const {url, info} of res?.data || []) {
+    profilesByUrl.set(url, info)
   }
 
   return profilesByUrl
 }
 
+export const fetchRelayProfiles = (urls: string[]) =>
+  appContext.dufflepudUrl
+    ? fetchRelayProfilesUsingProxy(appContext.dufflepudUrl, urls)
+    : fetchRelayProfilesDirectly(urls)
+
 export const {
   indexStore: relaysByUrl,
   deriveItem: deriveRelay,