perf: add toJSON to performance class

Added toJSON method to the InternalPerformance class as per the
convention followed in other performance classes and per the spec:
https://www.w3.org/TR/hr-time/#tojson-method

Fixes: #37623

Author: yashLadha

doc/api/perf_hooks.md

@@ -43,6 +43,14 @@ added: v8.5.0
 An object that can be used to collect performance metrics from the current
 Node.js instance. It is similar to [`window.performance`][] in browsers.
 
+### `performance.toJSON()`
+<!-- YAML
+added: REPLACEME
+-->
+
+An object which is JSON representation of the `performance` object. It
+is similar to [`window.performance.toJSON`][] in browsers.
+
 ### `performance.clearMarks([name])`
 <!-- YAML
 added: v8.5.0
@@ -1026,3 +1034,4 @@ require('some-module');
 [`process.hrtime()`]: process.md#process_process_hrtime_time
 [`timeOrigin`]: https://w3c.github.io/hr-time/#dom-performance-timeorigin
 [`window.performance`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/performance
+[`window.performance.toJSON`]: https://developer.mozilla.org/en-US/docs/Web/API/Performance/toJSON

lib/perf_hooks.js

@@ -59,6 +59,14 @@ class Performance extends EventTarget {
       timeOrigin: this.timeOrigin,
     }, opts)}`;
   }
+
+  toJSON() {
+    return {
+      nodeTiming: this.nodeTiming.toJSON(),
+      timeOrigin: this.timeOrigin,
+      eventLoopUtilization: this.eventLoopUtilization()
+    };
+  }
 }
 
 class InternalPerformance extends EventTarget {}

test/parallel/test-tojson-perf_hooks.js

@@ -0,0 +1,14 @@
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const { performance } = require('perf_hooks');
+
+// Test toJSON for performance object
+{
+  assert.strictEqual(typeof performance.toJSON, 'function');
+  const jsonObject = performance.toJSON();
+  assert.strictEqual(typeof jsonObject, 'object');
+  assert.strictEqual(jsonObject.timeOrigin, performance.timeOrigin);
+  assert.strictEqual(typeof jsonObject.nodeTiming, 'object');
+}