feat: BlockedQueue

src/functional/BlockedQueue.ts

@@ -0,0 +1,57 @@
+
+
+/**
+ * BlockedQueue
+ *
+ * provide a blocked queue for async operations
+ *
+ * @since 5.19.0
+ * @category Functional
+ */
+export class BlockedQueue<I = any> {
+
+  private _capacity: number;
+  private _notifyQueue: Array<Function>;
+
+  private _container: Array<I>;
+
+  constructor(capacity = 1000) {
+    this._capacity = capacity;
+    this._container = new Array(0);
+    this._notifyQueue = new Array(0);
+  }
+
+  async enQueue(item: I): Promise<void> {
+
+    if (this._container.length >= this._capacity) {
+
+      return new Promise((resolve) => {
+        this._notifyQueue.push(() => {
+          this._container.push(item);
+          resolve();
+        });
+      });
+
+    }
+
+    this._container.push(item);
+    return;
+
+  }
+
+  async deQueue(): Promise<I> {
+    if (this._container.length > 0) {
+      const item = this._container.shift();
+      if (this._notifyQueue.length > 0) {
+        this._notifyQueue.shift()();
+      }
+      return item;
+    }
+    return undefined;
+  }
+
+
+}
+
+
+export default BlockedQueue;

test/functional.test.ts

@@ -1,3 +1,4 @@
+import { BlockedQueue } from '../src/functional/BlockedQueue';
 import defineFunctionName from '../src/functional/defineFunctionName';
 import { hash } from '../src/functional/hash';
 import { hashEqual } from '../src/functional/hashEqual';
@@ -115,4 +116,43 @@ describe('functional', () => {
 
   });
 
+  it('should support blocked queue', async () => {
+
+    const q = new BlockedQueue(3);
+    const seq = [];
+
+    const enQ = (v: any) => q.enQueue(v).then(() => seq.push(`p${v}`));
+    const deQ = () => q.deQueue().then((value) => { seq.push(`d${value}`); return value; });
+    const p1 = Promise.all([
+      enQ(1),
+      enQ(2),
+      enQ(3),
+      enQ(4)
+    ]);
+
+    const p2 = Promise.all([
+      deQ(),
+      deQ(),
+      deQ(),
+      deQ(),
+      deQ()
+    ]);
+
+    await Promise.all([p1, p2]);
+
+    expect(seq).toStrictEqual([
+      'p1',
+      'p2',
+      'p3',
+      'd1',
+      'd2',
+      'd3',
+      'd4',
+      'dundefined',
+      'p4'
+    ]);
+
+
+  });
+
 });