Address PR comments

src/lease.ts

@@ -244,7 +244,7 @@ export class Lease extends EventEmitter {
     // far past the end of our key's TTL, there's no way we're going to be
     // able to renew it. Fire a "lost".
     if (Date.now() - this.lastKeepAlive > 2 * 1000 * this.ttl) {
-      this.emit('lost', new GRPCConnectFailedError('We lost connect to etcd and our lease has expired.'));
+      this.emit('lost', new GRPCConnectFailedError('We lost connection to etcd and our lease has expired.'));
       return this.close();
     }
 

src/util.ts

@@ -157,13 +157,23 @@ export function forOwn<T>(obj: T, iterator: <K extends keyof T>(value: T[K], key
  * fire on the emitter.
  */
 export function onceEvent(emitter: EventEmitter, ...events: string[]): Promise<any> {
-  return new Promise(resolve => {
-    const handler = (data: any) => {
-      events.forEach(name => emitter.removeListener(name, handler));
-      resolve(data);
+  return new Promise((resolve, reject) => {
+    const teardown: (() => void)[] = [];
+
+    const handler = (data: any, event: string) => {
+      teardown.forEach(t => t());
+      if (event === 'error') {
+        reject(data);
+      } else {
+        resolve(data);
+      }
     };
 
-    events.forEach(event => emitter.once(event, handler));
+    events.forEach(event => {
+      const fn = (data: any) => handler(data, event);
+      teardown.push(() => emitter.removeListener(event, fn));
+      emitter.once(event, fn);
+    });
   });
 }
 

src/watch.ts

@@ -321,13 +321,7 @@ export class WatchBuilder {
       this.namespace.applyToRequest(this.request),
     );
 
-    return onceEvent(watcher, 'connected', 'error').then(res => {
-      if (res instanceof Error) {
-        throw res;
-      }
-
-      return watcher;
-    });
+    return onceEvent(watcher, 'connected').then(() => watcher);
   }
 }