2 files changed, 99 insertions, 2 deletions

diff --git a/js/console.ts b/js/console.ts
index 311ca83b7..94ba43731 100644
--- a/js/console.ts
+++ b/js/console.ts
@@ -351,6 +351,9 @@ export function stringifyArgs(
 
 type PrintFunc = (x: string, isErr?: boolean) => void;
 
+const countMap = new Map<string, number>();
+const timerMap = new Map<string, number>();
+
 export class Console {
   // @internal
   constructor(private printFunc: PrintFunc) {}
@@ -387,7 +390,7 @@ export class Console {
    * ref: https://console.spec.whatwg.org/#assert
    */
   // tslint:disable-next-line:no-any
-  assert = (condition?: boolean, ...args: any[]): void => {
+  assert = (condition = false, ...args: any[]): void => {
     if (condition) {
       return;
     }
@@ -406,4 +409,68 @@ export class Console {
 
     this.error(`Assertion failed:`, ...args);
   };
+
+  count = (label = "default"): void => {
+    label = String(label);
+
+    if (countMap.has(label)) {
+      const current = countMap.get(label) || 0;
+      countMap.set(label, current + 1);
+    } else {
+      countMap.set(label, 1);
+    }
+
+    this.info(`${label}: ${countMap.get(label)}`);
+  };
+
+  countReset = (label = "default"): void => {
+    label = String(label);
+
+    if (countMap.has(label)) {
+      countMap.set(label, 0);
+    } else {
+      this.warn(`Count for '${label}' does not exist`);
+    }
+  };
+
+  time = (label = "default"): void => {
+    label = String(label);
+
+    if (timerMap.has(label)) {
+      this.warn(`Timer '${label}' already exists`);
+      return;
+    }
+
+    timerMap.set(label, Date.now());
+  };
+
+  // tslint:disable-next-line:no-any
+  timeLog = (label = "default", ...args: any[]): void => {
+    label = String(label);
+
+    if (!timerMap.has(label)) {
+      this.warn(`Timer '${label}' does not exists`);
+      return;
+    }
+
+    const startTime = timerMap.get(label) as number;
+    const duration = Date.now() - startTime;
+
+    this.info(`${label}: ${duration}ms`, ...args);
+  };
+
+  timeEnd = (label = "default"): void => {
+    label = String(label);
+
+    if (!timerMap.has(label)) {
+      this.warn(`Timer '${label}' does not exists`);
+      return;
+    }
+
+    const startTime = timerMap.get(label) as number;
+    timerMap.delete(label);
+    const duration = Date.now() - startTime;
+
+    this.info(`${label}: ${duration}ms`);
+  };
 }
diff --git a/js/console_test.ts b/js/console_test.ts
index 3e6bd6905..2946d3648 100644
--- a/js/console_test.ts
+++ b/js/console_test.ts
@@ -2,6 +2,10 @@
 import { test, assert, assertEqual } from "./test_util.ts";
 import { stringifyArgs } from "./console.ts";
 
+import { Console } from "./console.ts";
+import { libdeno } from "./libdeno";
+const console = new Console(libdeno.print);
+
 // tslint:disable-next-line:no-any
 function stringify(...args: any[]): string {
   return stringifyArgs(args);
@@ -114,7 +118,7 @@ test(function consoleTestStringifyCircular() {
   assertEqual(
     stringify(console),
     // tslint:disable-next-line:max-line-length
-    "Console { printFunc: [Function], log: [Function], debug: [Function], info: [Function], dir: [Function], warn: [Function], error: [Function], assert: [Function] }"
+    "Console { printFunc: [Function], log: [Function], debug: [Function], info: [Function], dir: [Function], warn: [Function], error: [Function], assert: [Function], count: [Function], countReset: [Function], time: [Function], timeLog: [Function], timeEnd: [Function] }"
   );
 });
 
@@ -136,6 +140,22 @@ test(function consoleTestStringifyWithDepth() {
   );
 });
 
+test(function consoleTestCallToStringOnLabel() {
+  const methods = ["count", "countReset", "time", "timeLog", "timeEnd"];
+
+  for (const method of methods) {
+    let hasCalled = false;
+
+    console[method]({
+      toString() {
+        hasCalled = true;
+      }
+    });
+
+    assertEqual(hasCalled, true);
+  }
+});
+
 test(function consoleTestError() {
   class MyError extends Error {
     constructor(errStr: string) {
@@ -159,6 +179,11 @@ test(function consoleDetachedLog() {
   const warn = console.warn;
   const error = console.error;
   const consoleAssert = console.assert;
+  const consoleCount = console.count;
+  const consoleCountReset = console.countReset;
+  const consoleTime = console.time;
+  const consoleTimeLog = console.timeLog;
+  const consoleTimeEnd = console.timeEnd;
   log("Hello world");
   dir("Hello world");
   debug("Hello world");
@@ -166,4 +191,9 @@ test(function consoleDetachedLog() {
   warn("Hello world");
   error("Hello world");
   consoleAssert(true);
+  consoleCount("Hello world");
+  consoleCountReset("Hello world");
+  consoleTime("Hello world");
+  consoleTimeLog("Hello world");
+  consoleTimeEnd("Hello world");
 });