Add Deno.symbols and move internal fields for test (#3693)

15 files changed, 92 insertions, 25 deletions

diff --git a/cli/js/console.ts b/cli/js/console.ts
index f366eb776..f5830b4a1 100644
--- a/cli/js/console.ts
+++ b/cli/js/console.ts
@@ -4,6 +4,7 @@ import { TypedArray } from "./types.ts";
 import { TextEncoder } from "./text_encoding.ts";
 import { File, stdout } from "./files.ts";
 import { cliTable } from "./console_table.ts";
+import { exposeForTest } from "./internals.ts";
 
 type ConsoleContext = Set<unknown>;
 type ConsoleOptions = Partial<{
@@ -363,9 +364,7 @@ function createObjectString(
   }
 }
 
-/** TODO Do not expose this from "deno" namespace.
- * @internal
- */
+/** @internal */
 export function stringifyArgs(
   args: unknown[],
   options: ConsoleOptions = {}
@@ -785,3 +784,7 @@ export function inspect(value: unknown, options?: ConsoleOptions): string {
     );
   }
 }
+
+// Expose these fields to internalObject for tests.
+exposeForTest("Console", Console);
+exposeForTest("stringifyArgs", stringifyArgs);
diff --git a/cli/js/console_test.ts b/cli/js/console_test.ts
index 126ad868b..b80dd8284 100644
--- a/cli/js/console_test.ts
+++ b/cli/js/console_test.ts
@@ -4,15 +4,19 @@ import { assert, assertEquals, test } from "./test_util.ts";
 // Some of these APIs aren't exposed in the types and so we have to cast to any
 // in order to "trick" TypeScript.
 const {
-  Console,
-  customInspect,
-  stringifyArgs,
   inspect,
   writeSync,
   stdout
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
 } = Deno as any;
 
+const customInspect = Deno.symbols.customInspect;
+const {
+  Console,
+  stringifyArgs
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+} = Deno[Deno.symbols.internal] as any;
+
 function stringify(...args: unknown[]): string {
   return stringifyArgs(args).replace(/\n$/, "");
 }
diff --git a/cli/js/deno.ts b/cli/js/deno.ts
index ed100ef22..a754bc4e2 100644
--- a/cli/js/deno.ts
+++ b/cli/js/deno.ts
@@ -100,7 +100,7 @@ export {
   Signal
 } from "./process.ts";
 export { transpileOnly, compile, bundle } from "./compiler_api.ts";
-export { inspect, customInspect } from "./console.ts";
+export { inspect } from "./console.ts";
 export { build, OperatingSystem, Arch } from "./build.ts";
 export { version } from "./version.ts";
 export const args: string[] = [];
@@ -110,18 +110,10 @@ export const args: string[] = [];
 /** @internal */
 export { core } from "./core.ts";
 
-/** @internal */
-export { setPrepareStackTrace } from "./error_stack.ts";
-
-// TODO Don't expose Console nor stringifyArgs.
-/** @internal */
-export { Console, stringifyArgs } from "./console.ts";
-// TODO Don't expose DomIterableMixin.
-/** @internal */
-export { DomIterableMixin } from "./mixins/dom_iterable.ts";
-
 /** The current process id of the runtime. */
 export let pid: number;
 
 /** Reflects the NO_COLOR environment variable: https://no-color.org/ */
 export let noColor: boolean;
+
+export { symbols } from "./symbols.ts";
diff --git a/cli/js/error_stack.ts b/cli/js/error_stack.ts
index 824fa6f87..7f19773bd 100644
--- a/cli/js/error_stack.ts
+++ b/cli/js/error_stack.ts
@@ -4,6 +4,7 @@
 import * as dispatch from "./dispatch.ts";
 import { sendSync } from "./dispatch_json.ts";
 import { assert } from "./util.ts";
+import { exposeForTest } from "./internals.ts";
 
 export interface Location {
   /** The full url for the module, e.g. `file://some/file.ts` or
@@ -271,3 +272,5 @@ function prepareStackTrace(
 export function setPrepareStackTrace(ErrorConstructor: typeof Error): void {
   ErrorConstructor.prepareStackTrace = prepareStackTrace;
 }
+
+exposeForTest("setPrepareStackTrace", setPrepareStackTrace);
diff --git a/cli/js/error_stack_test.ts b/cli/js/error_stack_test.ts
index 79711ace4..e4e44c77f 100644
--- a/cli/js/error_stack_test.ts
+++ b/cli/js/error_stack_test.ts
@@ -2,7 +2,7 @@
 import { test, assert } from "./test_util.ts";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
-const { setPrepareStackTrace } = Deno as any;
+const { setPrepareStackTrace } = Deno[Deno.symbols.internal] as any;
 
 interface CallSite {
   getThis(): unknown;
diff --git a/cli/js/globals.ts b/cli/js/globals.ts
index d06bc2f6f..c7f3b23f2 100644
--- a/cli/js/globals.ts
+++ b/cli/js/globals.ts
@@ -32,6 +32,8 @@ import * as request from "./request.ts";
 // symbols required.
 import { core } from "./core.ts";
 
+import { internalObject } from "./internals.ts";
+
 // During the build process, augmentations to the variable `window` in this
 // file are tracked and created as part of default library that is built into
 // Deno, we only need to declare the enough to compile Deno.
@@ -69,6 +71,10 @@ declare global {
 // A self reference to the global object.
 window.window = window;
 
+// Add internal object to Deno object.
+// This is not exposed as part of the Deno types.
+// @ts-ignore
+Deno[Deno.symbols.internal] = internalObject;
 // This is the Deno namespace, it is handled differently from other window
 // properties when building the runtime type library, as the whole module
 // is flattened into a single namespace.
diff --git a/cli/js/headers_test.ts b/cli/js/headers_test.ts
index 52a4594e6..15e1191f5 100644
--- a/cli/js/headers_test.ts
+++ b/cli/js/headers_test.ts
@@ -3,7 +3,7 @@ import { test, assert, assertEquals } from "./test_util.ts";
 const {
   stringifyArgs
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
-} = Deno as any;
+} = Deno[Deno.symbols.internal] as any;
 
 // Logic heavily copied from web-platform-tests, make
 // sure pass mostly header basic test
diff --git a/cli/js/internals.ts b/cli/js/internals.ts
new file mode 100644
index 000000000..6aae1be48
--- /dev/null
+++ b/cli/js/internals.ts
@@ -0,0 +1,16 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+export const internalSymbol = Symbol("Deno.internal");
+
+// The object where all the internal fields for testing will be living.
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export const internalObject: { [key: string]: any } = {};
+
+// Register a field to internalObject for test access,
+// through Deno[Deno.symbols.internal][name].
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export function exposeForTest(name: string, value: any): void {
+  Object.defineProperty(internalObject, name, {
+    value,
+    enumerable: false
+  });
+}
diff --git a/cli/js/internals_test.ts b/cli/js/internals_test.ts
new file mode 100644
index 000000000..055995fdf
--- /dev/null
+++ b/cli/js/internals_test.ts
@@ -0,0 +1,10 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { test, assert } from "./test_util.ts";
+
+test(function internalsExists(): void {
+  const {
+    stringifyArgs
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  } = Deno[Deno.symbols.internal] as any;
+  assert(!!stringifyArgs);
+});
diff --git a/cli/js/lib.deno_runtime.d.ts b/cli/js/lib.deno_runtime.d.ts
index f95236af7..d45ad2540 100644
--- a/cli/js/lib.deno_runtime.d.ts
+++ b/cli/js/lib.deno_runtime.d.ts
@@ -1507,10 +1507,6 @@ declare namespace Deno {
     colors: boolean;
     indentLevel: number;
   }>;
-  /** A symbol which can be used as a key for a custom method which will be called
-   * when `Deno.inspect()` is called, or when the object is logged to the console.
-   */
-  export const customInspect: unique symbol;
   /**
    * `inspect()` converts input into string that has the same format
    * as printed by `console.log(...)`;
@@ -1947,6 +1943,16 @@ declare namespace Deno {
   // @url js/deno.d.ts
 
   export const args: string[];
+
+  /** Special Deno related symbols. */
+  export const symbols: {
+    /** Symbol to access exposed internal Deno API */
+    readonly internal: unique symbol;
+    /** A symbol which can be used as a key for a custom method which will be called
+     * when `Deno.inspect()` is called, or when the object is logged to the console.
+     */
+    readonly customInspect: unique symbol;
+  };
 }
 
 // @url js/globals.ts
diff --git a/cli/js/mixins/dom_iterable.ts b/cli/js/mixins/dom_iterable.ts
index bbd1905ce..dcbd5150e 100644
--- a/cli/js/mixins/dom_iterable.ts
+++ b/cli/js/mixins/dom_iterable.ts
@@ -3,6 +3,7 @@
 import { DomIterable } from "../dom_types.ts";
 import { window } from "../window.ts";
 import { requiredArguments } from "../util.ts";
+import { exposeForTest } from "../internals.ts";
 
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 type Constructor<T = {}> = new (...args: any[]) => T;
@@ -10,7 +11,6 @@ type Constructor<T = {}> = new (...args: any[]) => T;
 /** Mixes in a DOM iterable methods into a base class, assumes that there is
  * a private data iterable that is part of the base class, located at
  * `[dataSymbol]`.
- * TODO Don't expose DomIterableMixin from "deno" namespace.
  */
 export function DomIterableMixin<K, V, TBase extends Constructor>(
   Base: TBase,
@@ -80,3 +80,5 @@ export function DomIterableMixin<K, V, TBase extends Constructor>(
 
   return DomIterable;
 }
+
+exposeForTest("DomIterableMixin", DomIterableMixin);
diff --git a/cli/js/mixins/dom_iterable_test.ts b/cli/js/mixins/dom_iterable_test.ts
index d3147b061..57e655989 100644
--- a/cli/js/mixins/dom_iterable_test.ts
+++ b/cli/js/mixins/dom_iterable_test.ts
@@ -21,7 +21,10 @@ function setup() {
     // This is using an internal API we don't want published as types, so having
     // to cast to any to "trick" TypeScript
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
-    DomIterable: (Deno as any).DomIterableMixin(Base, dataSymbol)
+    DomIterable: (Deno[Deno.symbols.internal] as any).DomIterableMixin(
+      Base,
+      dataSymbol
+    )
   };
 }
 
diff --git a/cli/js/symbols.ts b/cli/js/symbols.ts
new file mode 100644
index 000000000..4a8a6abfe
--- /dev/null
+++ b/cli/js/symbols.ts
@@ -0,0 +1,13 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { internalSymbol } from "./internals.ts";
+import { customInspect } from "./console.ts";
+
+/** Special Deno related symbols. */
+export const symbols = {
+  /** Symbol to access exposed internal Deno API */
+  internal: internalSymbol,
+  /** A symbol which can be used as a key for a custom method which will be called
+   * when `Deno.inspect()` is called, or when the object is logged to the console.
+   */
+  customInspect
+};
diff --git a/cli/js/symbols_test.ts b/cli/js/symbols_test.ts
new file mode 100644
index 000000000..26fe12375
--- /dev/null
+++ b/cli/js/symbols_test.ts
@@ -0,0 +1,7 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { test, assert } from "./test_util.ts";
+
+test(function symbolsExists(): void {
+  assert("internal" in Deno.symbols);
+  assert("customInspect" in Deno.symbols);
+});
diff --git a/cli/js/unit_tests.ts b/cli/js/unit_tests.ts
index d886d6f5d..084661ab8 100644
--- a/cli/js/unit_tests.ts
+++ b/cli/js/unit_tests.ts
@@ -25,6 +25,7 @@ import "./form_data_test.ts";
 import "./get_random_values_test.ts";
 import "./globals_test.ts";
 import "./headers_test.ts";
+import "./internals_test.ts";
 import "./link_test.ts";
 import "./location_test.ts";
 import "./make_temp_dir_test.ts";
@@ -42,6 +43,7 @@ import "./rename_test.ts";
 import "./request_test.ts";
 import "./resources_test.ts";
 import "./stat_test.ts";
+import "./symbols_test.ts";
 import "./symlink_test.ts";
 import "./text_encoding_test.ts";
 import "./timers_test.ts";