feat(ext/web): add performance.toJSON (#14548)

2 files changed, 13 insertions, 0 deletions

diff --git a/cli/dts/lib.deno.shared_globals.d.ts b/cli/dts/lib.deno.shared_globals.d.ts
index b96c56dba..d430c16b0 100644
--- a/cli/dts/lib.deno.shared_globals.d.ts
+++ b/cli/dts/lib.deno.shared_globals.d.ts
@@ -450,6 +450,7 @@ declare class Worker extends EventTarget {
 declare type PerformanceEntryList = PerformanceEntry[];
 
 declare class Performance {
+  /** Returns a timestamp representing the start of the performance measurement. */
   readonly timeOrigin: number;
   constructor();
 
@@ -490,6 +491,9 @@ declare class Performance {
    * ```
    */
   now(): number;
+
+  /** Returns a JSON representation of the performance object. */
+  toJSON(): any;
 }
 
 declare var performance: Performance;
diff --git a/cli/tests/unit/performance_test.ts b/cli/tests/unit/performance_test.ts
index 252a31fc4..917546e2c 100644
--- a/cli/tests/unit/performance_test.ts
+++ b/cli/tests/unit/performance_test.ts
@@ -27,6 +27,15 @@ Deno.test(function timeOrigin() {
   assert(Date.now() >= origin);
 });
 
+Deno.test(function performanceToJSON() {
+  const json = performance.toJSON();
+
+  assert("timeOrigin" in json);
+  assert(json.timeOrigin === performance.timeOrigin);
+  // check there are no other keys
+  assertEquals(Object.keys(json).length, 1);
+});
+
 Deno.test(function performanceMark() {
   const mark = performance.mark("test");
   assert(mark instanceof PerformanceMark);