1 files changed, 22 insertions, 0 deletions
diff --git a/cli/js/40_testing.js b/cli/js/40_testing.js
index 3058fcee3..740e950a3 100644
--- a/cli/js/40_testing.js
+++ b/cli/js/40_testing.js
@@ -685,6 +685,8 @@ function test(
   });
 }
 
+let registeredWarmupBench = false;
+
 // Main bench function provided by Deno.
 function bench(
   nameOrFnOrOptions,
@@ -695,6 +697,25 @@ function bench(
     return;
   }
 
+  if (!registeredWarmupBench) {
+    registeredWarmupBench = true;
+    const warmupBenchDesc = {
+      name: "<warmup>",
+      fn: function warmup() {},
+      async: false,
+      ignore: false,
+      baseline: false,
+      only: false,
+      sanitizeExit: true,
+      permissions: null,
+      warmup: true,
+    };
+    warmupBenchDesc.fn = wrapBenchmark(warmupBenchDesc);
+    const { id, origin } = ops.op_register_bench(warmupBenchDesc);
+    warmupBenchDesc.id = id;
+    warmupBenchDesc.origin = origin;
+  }
+
   let benchDesc;
   const defaults = {
     ignore: false,
@@ -777,6 +798,7 @@ function bench(
   const AsyncFunction = (async () => {}).constructor;
   benchDesc.async = AsyncFunction === benchDesc.fn.constructor;
   benchDesc.fn = wrapBenchmark(benchDesc);
+  benchDesc.warmup = false;
 
   const { id, origin } = ops.op_register_bench(benchDesc);
   benchDesc.id = id;