12 files changed, 112 insertions, 37 deletions

diff --git a/js/compiler.ts b/js/compiler.ts
index 046233442..d87309512 100644
--- a/js/compiler.ts
+++ b/js/compiler.ts
@@ -6,11 +6,12 @@ import { assetSourceCode } from "./assets";
 import * as deno from "./deno";
 import { globalEval } from "./global_eval";
 import { libdeno } from "./libdeno";
-import { window } from "./globals";
 import * as os from "./os";
 import { RawSourceMap } from "./types";
 import { assert, log, notImplemented } from "./util";
 
+const window = globalEval("this");
+
 const EOL = "\n";
 const ASSETS = "$asset$";
 const LIB_RUNTIME = "lib.deno_runtime.d.ts";
diff --git a/js/globals.ts b/js/globals.ts
index 5a0ca7cc6..6f29d97d4 100644
--- a/js/globals.ts
+++ b/js/globals.ts
@@ -1,23 +1,33 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
+// This is a "special" module, in that it define the global runtime scope of
+// Deno, and therefore it defines a lot of the runtime environemnt that code
+// is evaluated in.  We use this file to automatically build the runtime type
+// library.
+
+// Modules which will make up part of the global public API surface should be
+// imported as namespaces, so when the runtime tpye library is generated they
+// can be expressed as a namespace in the type library.
 import * as blob from "./blob";
+import * as consoleTypes from "./console";
+import * as domTypes from "./dom_types";
 import * as file from "./file";
-import * as formdata from "./form_data";
-import * as console_ from "./console";
-import * as fetch_ from "./fetch";
-import { Headers } from "./headers";
-import { globalEval } from "./global_eval";
-import { libdeno } from "./libdeno";
+import * as formData from "./form_data";
+import * as fetchTypes from "./fetch";
+import * as headers from "./headers";
 import * as textEncoding from "./text_encoding";
 import * as timers from "./timers";
 import * as urlSearchParams from "./url_search_params";
-import * as domTypes from "./dom_types";
+
+// These imports are not exposed and therefore are fine to just import the
+// symbols required.
+import { globalEval } from "./global_eval";
+import { libdeno } from "./libdeno";
 
 // 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.
-
+// Deno, we only need to declare the enough to compile Deno.
 declare global {
-  const console: console_.Console;
+  const console: consoleTypes.Console;
   const setTimeout: typeof timers.setTimeout;
   // tslint:disable-next-line:variable-name
   const TextEncoder: typeof textEncoding.TextEncoder;
@@ -25,26 +35,41 @@ declare global {
 
 // A reference to the global object.
 export const window = globalEval("this");
+// A self reference to the global object.
 window.window = window;
 
-window.setTimeout = timers.setTimeout;
-window.setInterval = timers.setInterval;
-window.clearTimeout = timers.clearTimer;
-window.clearInterval = timers.clearTimer;
-
-window.console = new console_.Console(libdeno.print);
-window.TextEncoder = textEncoding.TextEncoder;
-window.TextDecoder = textEncoding.TextDecoder;
+// Globally available functions and object instances.
 window.atob = textEncoding.atob;
 window.btoa = textEncoding.btoa;
+window.fetch = fetchTypes.fetch;
+window.clearTimeout = timers.clearTimer;
+window.clearInterval = timers.clearTimer;
+window.console = new consoleTypes.Console(libdeno.print);
+window.setTimeout = timers.setTimeout;
+window.setInterval = timers.setInterval;
 
+// When creating the runtime type library, we use modifications to `window` to
+// determine what is in the global namespace.  When we put a class in the
+// namespace, we also need its global instance type as well, otherwise users
+// won't be able to refer to instances.
+// We have to export the type aliases, so that TypeScript _knows_ they are
+// being used, which it cannot statically determine within this module.
+window.Blob = blob.DenoBlob;
+export type Blob = blob.DenoBlob;
+window.File = file.DenoFile;
+export type File = file.DenoFile;
 window.URLSearchParams = urlSearchParams.URLSearchParams;
+export type URLSearchParams = urlSearchParams.URLSearchParams;
 
-window.fetch = fetch_.fetch;
+// Using the `as` keyword to use standard compliant interfaces as the Deno
+// implementations contain some implementation details we wouldn't want to
+// expose in the runtime type library.
+window.Headers = headers.Headers as domTypes.HeadersConstructor;
+export type Headers = domTypes.Headers;
+window.FormData = formData.FormData as domTypes.FormDataConstructor;
+export type FormData = domTypes.FormData;
 
-// using the `as` keyword to mask the internal types when generating the
-// runtime library
-window.Headers = Headers as domTypes.HeadersConstructor;
-window.Blob = blob.DenoBlob;
-window.File = file.DenoFile;
-window.FormData = formdata.FormData as domTypes.FormDataConstructor;
+// While these are classes, they have their global instance types created in
+// other type definitions, therefore we do not have to include them here.
+window.TextEncoder = textEncoding.TextEncoder;
+window.TextDecoder = textEncoding.TextDecoder;
diff --git a/js/headers_test.ts b/js/headers_test.ts
index 6980c3d7e..e40efcda6 100644
--- a/js/headers_test.ts
+++ b/js/headers_test.ts
@@ -169,3 +169,11 @@ test(function headerSymbolIteratorSuccess() {
     assertEqual(value, headers.get(key));
   }
 });
+
+test(function headerTypesAvailable() {
+  function newHeaders(): Headers {
+    return new Headers();
+  }
+  const headers = newHeaders();
+  assert(headers instanceof Headers);
+});
diff --git a/js/main.ts b/js/main.ts
index 176f098c7..b0c7ed6d4 100644
--- a/js/main.ts
+++ b/js/main.ts
@@ -1,4 +1,7 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
+// We need to make sure this module loads, for its side effects.
+import "./globals";
+
 import * as flatbuffers from "./flatbuffers";
 import * as msg from "gen/msg_generated";
 import { assert, log, setLogDebug } from "./util";
diff --git a/js/repl.ts b/js/repl.ts
index 3139330f6..ae457e8e4 100644
--- a/js/repl.ts
+++ b/js/repl.ts
@@ -6,7 +6,9 @@ import * as deno from "./deno";
 import { close } from "./files";
 import * as dispatch from "./dispatch";
 import { exit } from "./os";
-import { window } from "./globals";
+import { globalEval } from "./global_eval";
+
+const window = globalEval("this");
 
 function startRepl(historyFile: string): number {
   const builder = flatbuffers.createBuilder();
diff --git a/tests/error_003_typescript.ts.out b/tests/error_003_typescript.ts.out
index e2b5cae05..20f5c95d0 100644
--- a/tests/error_003_typescript.ts.out
+++ b/tests/error_003_typescript.ts.out
@@ -4,7 +4,7 @@
 [WILDCARD]~~~~~~
 
   $asset$/lib.deno_runtime.d.tsILDCARD]
-[WILDCARD]declare const console: console_.Console;
+[WILDCARD]declare const console: consoleTypes.Console;
 [WILDCARD]~~~~~~~
 [WILDCARD]'console' is declared here.
 
diff --git a/tests/error_008_checkjs.js.out b/tests/error_008_checkjs.js.out
index 9220efaf1..793c2f68c 100644
--- a/tests/error_008_checkjs.js.out
+++ b/tests/error_008_checkjs.js.out
@@ -4,7 +4,7 @@
 [WILDCARD]~~~~~~
 
   $asset$/lib.deno_runtime.d.tsILDCARD]
-[WILDCARD]declare const console: console_.Console;
+[WILDCARD]declare const console: consoleTypes.Console;
 [WILDCARD]~~~~~~~
 [WILDCARD]'console' is declared here.
 
diff --git a/tools/ts_library_builder/README.md b/tools/ts_library_builder/README.md
index de1305dca..e2701f0fb 100644
--- a/tools/ts_library_builder/README.md
+++ b/tools/ts_library_builder/README.md
@@ -72,17 +72,16 @@ like this:
   - This process assumes that all the modules that feed `js/deno.ts` will have a
     public type API that does not have name conflicts.
 - We process the `js/globals.ts` file to generate the global namespace.
-  - Currently we create a `"globals"` module which will contain the type
-    definitions.
   - We create a `Window` interface and a `global` scope augmentation namespace.
   - We iterate over augmentations to the `window` variable declared in the file,
     extract the type information and apply it to both a global variable
     declaration and a property on the `Window` interface.
+  - We identify any type aliases in the module and declare them globally.
 - We take each namespace import to `js/globals.ts`, we resolve the emitted
-  declaration `.d.ts` file and create it as its own namespace withing the
-  `"globals"` module. It is unsafe to just flatten these, because there is a
-  high risk of collisions, but also, it makes authoring the types easier within
-  the generated interface and variable declarations.
+  declaration `.d.ts` file and create it as its own namespace within the global
+  scope. It is unsafe to just flatten these, because there is a high risk of
+  collisions, but also, it makes authoring the types easier within the generated
+  interface and variable declarations.
 - We then validate the resulting definition file and write it out to the
   appropriate build path.
 
diff --git a/tools/ts_library_builder/ast_util.ts b/tools/ts_library_builder/ast_util.ts
index 528036b99..85d0a3480 100644
--- a/tools/ts_library_builder/ast_util.ts
+++ b/tools/ts_library_builder/ast_util.ts
@@ -42,6 +42,22 @@ export function addSourceComment(
   );
 }
 
+/** Add a declaration of a type alias to a node */
+export function addTypeAlias(
+  node: StatementedNode,
+  name: string,
+  type: string,
+  hasDeclareKeyword = false,
+  jsdocs?: JSDoc[]
+) {
+  return node.addTypeAlias({
+    name,
+    type,
+    docs: jsdocs && jsdocs.map(jsdoc => jsdoc.getText()),
+    hasDeclareKeyword
+  });
+}
+
 /** Add a declaration of a variable to a node */
 export function addVariableDeclaration(
   node: StatementedNode,
diff --git a/tools/ts_library_builder/build_library.ts b/tools/ts_library_builder/build_library.ts
index af3fb599d..e1a64215f 100644
--- a/tools/ts_library_builder/build_library.ts
+++ b/tools/ts_library_builder/build_library.ts
@@ -21,7 +21,8 @@ import {
   loadFiles,
   logDiagnostics,
   namespaceSourceFile,
-  normalizeSlashes
+  normalizeSlashes,
+  addTypeAlias
 } from "./ast_util";
 
 export interface BuildLibraryOptions {
@@ -216,6 +217,16 @@ export function mergeGlobal({
     addInterfaceProperty(interfaceDeclaration, property, type);
   }
 
+  // We need to copy over any type aliases
+  for (const typeAlias of sourceFile.getTypeAliases()) {
+    addTypeAlias(
+      targetSourceFile,
+      typeAlias.getName(),
+      typeAlias.getType().getText(sourceFile),
+      true
+    );
+  }
+
   // We need to ensure that we only namespace each source file once, so we
   // will use this map for tracking that.
   const sourceFileMap = new Map<SourceFile, string>();
diff --git a/tools/ts_library_builder/test.ts b/tools/ts_library_builder/test.ts
index 3a18fe29c..71b1d19a0 100644
--- a/tools/ts_library_builder/test.ts
+++ b/tools/ts_library_builder/test.ts
@@ -149,7 +149,15 @@ test(function buildLibraryMerge() {
     variableDeclarations[4].getType().getText(),
     `typeof moduleD.reprocess`
   );
-  assertEqual(variableDeclarations.length, 5);
+  assertEqual(
+    variableDeclarations[5].getType().getText(),
+    `typeof moduleC.Bar`
+  );
+  assertEqual(variableDeclarations.length, 6);
+  const typeAliases = targetSourceFile.getTypeAliases();
+  assertEqual(typeAliases[0].getName(), "Bar");
+  assertEqual(typeAliases[0].getType().getText(), "moduleC.Bar");
+  assertEqual(typeAliases.length, 1);
 });
 
 // TODO author unit tests for `ast_util.ts`
diff --git a/tools/ts_library_builder/testdata/globals.ts b/tools/ts_library_builder/testdata/globals.ts
index e80862025..9d117c794 100644
--- a/tools/ts_library_builder/testdata/globals.ts
+++ b/tools/ts_library_builder/testdata/globals.ts
@@ -8,3 +8,5 @@ foobarbaz.bar = new moduleC.Bar();
 foobarbaz.qat = moduleC.qat;
 foobarbaz.process = moduleE.process;
 foobarbaz.reprocess = moduleD.reprocess;
+foobarbaz.Bar = moduleC.Bar;
+export type Bar = moduleC.Bar;