added basic queue from https://medium.com/@karenmarkosyan/how-to-manage-promises-into-dynamic-queue-with-vanilla-javascript-9d0d1f8d4df5

Author: lee-leonardo

lib/promiseQueue.js

@@ -0,0 +1,50 @@
+export class PromiseQueue {
+  static queue = [];
+  static pending = false;
+  static stop = false;
+
+  static enqueue(promise) {
+    return new Promise((resolve, reject) => {
+      this.queue.push({
+        promise,
+        resolve,
+        reject,
+      });
+      this.dequeue();
+    });
+  }
+
+  static dequeue() {
+    if (this.workingOnPromise) {
+      return false;
+    }
+    if (this.stop) {
+      this.queue = [];
+      this.stop = false;
+      return;
+    }
+    const item = this.queue.shift();
+    if (!item) {
+      return false;
+    }
+    try {
+      this.workingOnPromise = true;
+      item.promise()
+        .then((value) => {
+          this.workingOnPromise = false;
+          item.resolve(value);
+          this.dequeue();
+        })
+        .catch(err => {
+          this.workingOnPromise = false;
+          item.reject(err);
+          this.dequeue();
+        })
+    } catch (err) {
+      this.workingOnPromise = false;
+      item.reject(err);
+      this.dequeue();
+    }
+    return true;
+  }
+}