Merge c7e5a67 into e64e333

lib/internal/queue.js

@@ -132,16 +132,17 @@ export default function queue(worker, concurrency, payload) {
 
     const eventMethod = (name) => (handler) => {
         if (!handler) {
-            return new Promise((resolve, reject) => {
+            const p = new Promise((resolve, reject) => {
                 once(name, (err, data) => {
                     if (err) return reject(err)
                     resolve(data)
                 })
             })
+            _maybeDrain([]);
+            return p;
         }
         off(name)
         on(name, handler)
-
     }
 
     var isProcessing = false;

test/queue.js

@@ -125,6 +125,26 @@ describe('queue', function(){
         done();
     });
 
+    it('correctly awaitable', async () => {
+        var q = async.queue((t, cb) => cb(null, t));
+        q.push(1, () => {});
+        // double await
+        const p = await q.drain();
+        await p;
+
+        // await on empty queue
+        const p2 = q.drain();
+        await p2;
+
+        // await on queue refilled
+        q.push(1, () => {});
+        const p3 = q.drain();
+        await p3;
+        expect(p).to.not.eql(p2);
+        expect(p).to.not.eql(p3);
+        expect(p2).to.not.eql(p3);
+    });
+
     it('error propagation', (done) => {
         var results = [];