Feat/get priority

README.md

@@ -51,6 +51,7 @@ Heapify's design strives for reliability, with strong test coverage and focus on
   - [pop()](#pop)
   - [push(key, priority)](#pushkey-priority)
   - [size](#size)
+  - [getPriority(key)](#getpriority-key)
 - [Benchmark](#benchmark)
 - [Contributing](#contributing)
 
@@ -233,6 +234,18 @@ queue.pop();
 queue.size;  // 0
 ```
 
+### getPriority(key)
+
+Gets the _priority_ of the given `key`.
+
+Example:
+
+```js
+const queue = new MinQueue();
+queue.push(1, 10);
+queue.getPriority(1); // 10
+```
+
 ## Benchmark
 
 Here's a table comparing Heapify with other implementations (times are in milliseconds):

src/heapify.ts

@@ -170,6 +170,11 @@ export class MinQueue {
         return this._keys[ROOT_INDEX];
     }
 
+    getPriority(key: number): number | undefined {
+        const index = this._keys.findIndex(k => k === key);
+        return index === -1 ? undefined : this._priorities[index];
+    }
+
     private removePoppedElement(): void {
         if (this._hasPoppedElement) {
             // since root element was already deleted from pop, replace with last and bubble down

test/heapify.test.ts

@@ -240,4 +240,20 @@ describe("MinQueue", () => {
         // v0.4.0 returns 3 here
         assert.strictEqual(queue.pop(), 2);
     });
+
+    test("get priority of given key", () => {
+        const queue = new MinQueue();
+        queue.push(1, 10);
+        queue.push(2, 20);
+        queue.push(3, 15);
+        assert.strictEqual(queue.getPriority(1), 10);
+        assert.strictEqual(queue.getPriority(2), 20);
+        assert.strictEqual(queue.getPriority(3), 15);
+    })
+
+    test("get priority returns undefined if key not found", () => {
+        const queue = new MinQueue();
+        queue.push(1, 10);
+        assert.strictEqual(queue.getPriority(2), undefined);
+    })
 });