style: Add comments, tidy types.

Author: timoxley

src/StreamrClient.ts

@@ -357,7 +357,7 @@ export class StreamrClient extends EventEmitter { // eslint-disable-line no-rede
         let subTask: Todo
         let sub: Todo
         const hasResend = !!(opts.resend || opts.from || opts.to || opts.last)
-        const onEnd = (err: Error) => {
+        const onEnd = (err?: Error) => {
             if (sub && typeof onMessage === 'function') {
                 sub.off('message', onMessage)
             }

src/stream/KeyExchange.js

@@ -181,9 +181,7 @@ async function subscribeToKeyExchangeStream(client, onKeyExchangeMessage) {
     const publisherId = await client.getUserId()
     const streamId = getKeyExchangeStreamId(publisherId)
     const sub = await client.subscribe(streamId, onKeyExchangeMessage)
-    sub.on('error', () => {
-
-    })
+    sub.on('error', () => {}) // errors should not shut down subscription
     return sub
 }
 
@@ -362,7 +360,7 @@ async function SubscriberKeyExhangeSubscription(client, getGroupKeyStore, encryp
     }
 
     sub = await subscribeToKeyExchangeStream(client, onKeyExchangeMessage)
-    sub.on('error', () => {})
+    sub.on('error', () => {}) // errors should not shut down subscription
     return sub
 }
 

src/utils/index.ts

@@ -148,8 +148,7 @@ export function CacheAsyncFn(asyncFn: Parameters<typeof pMemoize>[0], {
     maxSize = 10000,
     maxAge = 30 * 60 * 1000, // 30 minutes
     cachePromiseRejection = false,
-    onEviction = () => {
-    },
+    onEviction = () => {},
     ...opts
 } = {}) {
     const cache = new LRU<unknown, { data: unknown, maxAge: number }>({
@@ -230,7 +229,7 @@ export function Defer<T>(executor: (...args: Parameters<Promise<T>['then']>) =>
         reject = _reject
         executor(resolve, reject)
     })
-    p.catch(() => {})
+    p.catch(() => {}) // prevent unhandledrejection
 
     function wrap(fn: F.Function) {
         return async (...args: unknown[]) => {