5 files changed, 27 insertions, 8 deletions
diff --git a/docs/contributing/style_guide.md b/docs/contributing/style_guide.md
index ed23f31e1..0bd7c628f 100644
--- a/docs/contributing/style_guide.md
+++ b/docs/contributing/style_guide.md
@@ -314,3 +314,16 @@ export function foo(): string {
 `https://deno.land/std/` is intended to be baseline functionality that all Deno
 programs can rely on. We want to guarantee to users that this code does not
 include potentially unreviewed third party code.
+
+#### Document and maintain browser compatiblity.
+
+If a module is browser compatible, include the following in the JSDoc at the top
+of the module:
+
+```ts
+/** This module is browser compatible. */
+```
+
+Maintain browser compatibility for such a module by either not using the global
+`Deno` namespace or feature-testing for it. Make sure any new dependencies are
+also browser compatible.
diff --git a/std/fmt/colors.ts b/std/fmt/colors.ts
index 6a06af20e..a020657d9 100644
--- a/std/fmt/colors.ts
+++ b/std/fmt/colors.ts
@@ -1,6 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-/**
- * A module to print ANSI terminal colors. Inspired by chalk, kleur, and colors
+/** A module to print ANSI terminal colors. Inspired by chalk, kleur, and colors
  * on npm.
  *
  * ```
@@ -10,8 +9,10 @@
  *
  * This module supports `NO_COLOR` environmental variable disabling any coloring
  * if `NO_COLOR` is set.
- */
-const { noColor } = Deno;
+ *
+ * This module is browser compatible. */
+
+const noColor = globalThis.Deno?.noColor ?? true;
 
 interface Code {
   open: string;
diff --git a/std/testing/asserts.ts b/std/testing/asserts.ts
index d3f8bb678..ce7214998 100644
--- a/std/testing/asserts.ts
+++ b/std/testing/asserts.ts
@@ -1,4 +1,7 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+/** This module is browser compatible. Do not rely on good formatting of values
+ * for AssertionError messages in browsers. */
+
 import { red, green, white, gray, bold } from "../fmt/colors.ts";
 import diff, { DiffType, DiffResult } from "./diff.ts";
 
@@ -17,7 +20,7 @@ export class AssertionError extends Error {
 }
 
 function format(v: unknown): string {
-  let string = Deno.inspect(v);
+  let string = globalThis.Deno ? Deno.inspect(v) : String(v);
   if (typeof v == "string") {
     string = `"${string.replace(/(?=["\\])/g, "\\")}"`;
   }
@@ -254,7 +257,7 @@ export function assertStrContains(
 ): void {
   if (!actual.includes(expected)) {
     if (!msg) {
-      msg = `actual: "${actual}" expected to contains: "${expected}"`;
+      msg = `actual: "${actual}" expected to contain: "${expected}"`;
     }
     throw new AssertionError(msg);
   }
@@ -286,7 +289,7 @@ export function assertArrayContains(
     return;
   }
   if (!msg) {
-    msg = `actual: "${actual}" expected to contains: "${expected}"`;
+    msg = `actual: "${actual}" expected to contain: "${expected}"`;
     msg += "\n";
     msg += `missing: ${missing}`;
   }
diff --git a/std/testing/asserts_test.ts b/std/testing/asserts_test.ts
index 14eabca61..fb25d46cf 100644
--- a/std/testing/asserts_test.ts
+++ b/std/testing/asserts_test.ts
@@ -169,7 +169,7 @@ test("testingAssertStringContainsThrow", function (): void {
   } catch (e) {
     assert(
       e.message ===
-        `actual: "Denosaurus from Jurassic" expected to contains: "Raptor"`
+        `actual: "Denosaurus from Jurassic" expected to contain: "Raptor"`
     );
     assert(e instanceof AssertionError);
     didThrow = true;
diff --git a/std/testing/diff.ts b/std/testing/diff.ts
index 97baa089f..da1e827ac 100644
--- a/std/testing/diff.ts
+++ b/std/testing/diff.ts
@@ -1,4 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+/** This module is browser compatible. */
+
 interface FarthestPoint {
   y: number;
   id: number;