(#85) Added higher resolution wait

Author: s1hofmann

lib/sleep.function.spec.ts

@@ -1,16 +1,32 @@
-import { sleep } from "./sleep.function";
+import {busyWaitForNanoSeconds, sleep} from "./sleep.function";
 
 describe("sleep", () => {
-  it("should resolve after x ms", async () => {
-    // GIVEN
-    const timeout = 500;
+    it("should resolve after x ms", async () => {
+        // GIVEN
+        const timeout = 500;
 
-    // WHEN
-    const before = Date.now();
-    await sleep(timeout);
-    const after = Date.now();
+        // WHEN
+        const before = Date.now();
+        await sleep(timeout);
+        const after = Date.now();
 
-    // THEN
-    expect(after - before).toBeGreaterThanOrEqual(timeout);
-  });
+        // THEN
+        expect(after - before).toBeGreaterThanOrEqual(timeout);
+    });
+});
+
+describe("busyWaitForNanoSeconds", () => {
+    it("should resolve after x ns", async () => {
+        // GIVEN
+        const timeoutNs = 5000;
+        const timeoutMs = 5;
+
+        // WHEN
+        const before = Date.now();
+        await busyWaitForNanoSeconds(timeoutNs);
+        const after = Date.now();
+
+        // THEN
+        expect(after - before).toBeGreaterThanOrEqual(timeoutMs);
+    });
 });

lib/sleep.function.ts

@@ -1,3 +1,16 @@
 export const sleep = async (ms: number) => {
   return new Promise(resolve => setTimeout(resolve, ms));
 };
+
+export const busyWaitForNanoSeconds = (duration: number) => {
+  return new Promise(res => {
+    const start = process.hrtime.bigint();
+    let isWaiting = true;
+    while (isWaiting) {
+      if ((process.hrtime.bigint() - start) > duration) {
+        isWaiting = false;
+      }
+    }
+    res();
+  });
+};