feat: Support named exports on bundles. (#3352)

cli/js/bundler.ts

+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+import { Console } from "./console.ts";
+import * as dispatch from "./dispatch.ts";
+import { sendSync } from "./dispatch_json.ts";
+import { TextEncoder } from "./text_encoding.ts";
+import { assert, commonPath, humanFileSize } from "./util.ts";
+import { writeFileSync } from "./write_file.ts";
+
+declare global {
+  const console: Console;
+}
+
+const BUNDLE_LOADER = "bundle_loader.js";
+
+const encoder = new TextEncoder();
+
+let bundleLoader: string;
+
+let rootExports: string[] | undefined;
+
+/** Given a fileName and the data, emit the file to the file system. */
+export function emitBundle(
+  rootNames: string[],
+  fileName: string | undefined,
+  data: string,
+  sourceFiles: readonly ts.SourceFile[]
+): void {
+  // if the fileName is set to an internal value, just noop
+  if (fileName && fileName.startsWith("$deno$")) {
+    return;
+  }
+  // This should never happen at the moment, but this code can't currently
+  // support it
+  assert(
+    rootNames.length === 1,
+    "Only single root modules supported for bundling."
+  );
+  if (!bundleLoader) {
+    bundleLoader = sendSync(dispatch.OP_FETCH_ASSET, { name: BUNDLE_LOADER });
+  }
+
+  // when outputting to AMD and a single outfile, TypeScript makes up the module
+  // specifiers which are used to define the modules, and doesn't expose them
+  // publicly, so we have to try to replicate
+  const sources = sourceFiles.map(sf => sf.fileName);
+  const sharedPath = commonPath(sources);
+  const rootName = rootNames[0].replace(sharedPath, "").replace(/\.\w+$/i, "");
+  let instantiate: string;
+  if (rootExports && rootExports.length) {
+    instantiate = `const __rootExports = instantiate("${rootName}");\n`;
+    for (const rootExport of rootExports) {
+      if (rootExport === "default") {
+        instantiate += `export default __rootExports["${rootExport}"];\n`;
+      } else {
+        instantiate += `export const ${rootExport} = __rootExports["${rootExport}"];\n`;
+      }
+    }
+  } else {
+    instantiate = `instantiate("${rootName}");\n`;
+  }
+  const bundle = `${bundleLoader}\n${data}\n${instantiate}`;
+  if (fileName) {
+    const encodedData = encoder.encode(bundle);
+    console.warn(`Emitting bundle to "${fileName}"`);
+    writeFileSync(fileName, encodedData);
+    console.warn(`${humanFileSize(encodedData.length)} emitted.`);
+  } else {
+    console.log(bundle);
+  }
+}
+
+/** Set the rootExports which will by the `emitBundle()` */
+export function setRootExports(
+  program: ts.Program,
+  rootModules: string[]
+): void {
+  // get a reference to the type checker, this will let us find symbols from
+  // the AST.
+  const checker = program.getTypeChecker();
+  assert(rootModules.length === 1);
+  // get a reference to the main source file for the bundle
+  const mainSourceFile = program.getSourceFile(rootModules[0]);
+  assert(mainSourceFile);
+  // retrieve the internal TypeScript symbol for this AST node
+  const mainSymbol = checker.getSymbolAtLocation(mainSourceFile);
+  if (!mainSymbol) {
+    return;
+  }
+  rootExports = checker
+    .getExportsOfModule(mainSymbol)
+    // .getExportsOfModule includes type only symbols which are exported from
+    // the module, so we need to try to filter those out.  While not critical
+    // someone looking at the bundle would think there is runtime code behind
+    // that when there isn't.  There appears to be no clean way of figuring that
+    // out, so inspecting SymbolFlags that might be present that are type only
+    .filter(
+      sym =>
+        !(
+          sym.flags & ts.SymbolFlags.Interface ||
+          sym.flags & ts.SymbolFlags.TypeLiteral ||
+          sym.flags & ts.SymbolFlags.Signature ||
+          sym.flags & ts.SymbolFlags.TypeParameter ||
+          sym.flags & ts.SymbolFlags.TypeAlias ||
+          sym.flags & ts.SymbolFlags.Type ||
+          sym.flags & ts.SymbolFlags.Namespace ||
+          sym.flags & ts.SymbolFlags.InterfaceExcludes ||
+          sym.flags & ts.SymbolFlags.TypeParameterExcludes ||
+          sym.flags & ts.SymbolFlags.TypeAliasExcludes
+        )
+    )
+    .map(sym => sym.getName());
+}

cli/js/compiler.ts

@@ -4,6 +4,7 @@
 import "./globals.ts";
 import "./ts_global.d.ts";
 
+import { emitBundle, setRootExports } from "./bundler.ts";
 import { bold, cyan, yellow } from "./colors.ts";
 import { Console } from "./console.ts";
 import { core } from "./core.ts";
@@ -12,13 +13,11 @@ import { cwd } from "./dir.ts";
 import * as dispatch from "./dispatch.ts";
 import { sendAsync, sendSync } from "./dispatch_json.ts";
 import * as os from "./os.ts";
-import { TextEncoder } from "./text_encoding.ts";
 import { getMappedModuleName, parseTypeDirectives } from "./type_directives.ts";
 import { assert, notImplemented } from "./util.ts";
 import * as util from "./util.ts";
 import { window } from "./window.ts";
 import { postMessage, workerClose, workerMain } from "./workers.ts";
-import { writeFileSync } from "./write_file.ts";
 
 // Warning! The values in this enum are duplicated in cli/msg.rs
 // Update carefully!
@@ -52,7 +51,6 @@ window["denoMain"] = denoMain;
 
 const ASSETS = "$asset$";
 const OUT_DIR = "$deno$";
-const BUNDLE_LOADER = "bundle_loader.js";
 
 /** The format of the work message payload coming from the privileged side */
 type CompilerRequest = {
@@ -188,6 +186,12 @@ class SourceFile {
       throw new Error("SourceFile has already been processed.");
     }
     assert(this.sourceCode != null);
+    // we shouldn't process imports for files which contain the nocheck pragma
+    // (like bundles)
+    if (this.sourceCode.match(/\/{2}\s+@ts-nocheck/)) {
+      util.log(`Skipping imports for "${this.filename}"`);
+      return [];
+    }
     const preProcessedFileInfo = ts.preProcessFile(this.sourceCode, true, true);
     this.processed = true;
     const files = (this.importedFiles = [] as Array<[string, string]>);
@@ -302,63 +306,12 @@ async function processImports(
   return sourceFiles;
 }
 
-/** Utility function to turn the number of bytes into a human readable
- * unit */
-function humanFileSize(bytes: number): string {
-  const thresh = 1000;
-  if (Math.abs(bytes) < thresh) {
-    return bytes + " B";
-  }
-  const units = ["kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"];
-  let u = -1;
-  do {
-    bytes /= thresh;
-    ++u;
-  } while (Math.abs(bytes) >= thresh && u < units.length - 1);
-  return `${bytes.toFixed(1)} ${units[u]}`;
-}
-
 /** Ops to rest for caching source map and compiled js */
 function cache(extension: string, moduleId: string, contents: string): void {
   util.log("compiler::cache", { extension, moduleId });
   sendSync(dispatch.OP_CACHE, { extension, moduleId, contents });
 }
 
-const encoder = new TextEncoder();
-
-/** Given a fileName and the data, emit the file to the file system. */
-function emitBundle(
-  rootNames: string[],
-  fileName: string | undefined,
-  data: string,
-  sourceFiles: readonly ts.SourceFile[]
-): void {
-  // For internal purposes, when trying to emit to `$deno$` just no-op
-  if (fileName && fileName.startsWith("$deno$")) {
-    console.warn("skipping emitBundle", fileName);
-    return;
-  }
-  const loader = fetchAsset(BUNDLE_LOADER);
-  // when outputting to AMD and a single outfile, TypeScript makes up the module
-  // specifiers which are used to define the modules, and doesn't expose them
-  // publicly, so we have to try to replicate
-  const sources = sourceFiles.map(sf => sf.fileName);
-  const sharedPath = util.commonPath(sources);
-  rootNames = rootNames.map(id =>
-    id.replace(sharedPath, "").replace(/\.\w+$/i, "")
-  );
-  const instantiate = `instantiate(${JSON.stringify(rootNames)});\n`;
-  const bundle = `${loader}\n${data}\n${instantiate}`;
-  if (fileName) {
-    const encodedData = encoder.encode(bundle);
-    console.warn(`Emitting bundle to "${fileName}"`);
-    writeFileSync(fileName, encodedData);
-    console.warn(`${humanFileSize(encodedData.length)} emitted.`);
-  } else {
-    console.log(bundle);
-  }
-}
-
 /** Returns the TypeScript Extension enum for a given media type. */
 function getExtension(fileName: string, mediaType: MediaType): ts.Extension {
   switch (mediaType) {
@@ -577,7 +530,7 @@ class Host implements ts.CompilerHost {
     try {
       assert(sourceFiles != null);
       if (this._requestType === CompilerRequestType.Bundle) {
-        emitBundle(this._rootNames, this._outFile, data, sourceFiles!);
+        emitBundle(this._rootNames, this._outFile, data, sourceFiles);
       } else {
         assert(sourceFiles.length == 1);
         const url = sourceFiles[0].fileName;
@@ -704,6 +657,9 @@ window.compilerMain = function compilerMain(): void {
           // warning so it goes to stderr instead of stdout
           console.warn(`Bundling "${resolvedRootModules.join(`", "`)}"`);
         }
+        if (request.type === CompilerRequestType.Bundle) {
+          setRootExports(program, resolvedRootModules);
+        }
         const emitResult = program.emit();
         emitSkipped = emitResult.emitSkipped;
         // emitResult.diagnostics is `readonly` in TS3.5+ and can't be assigned

cli/js/util.ts

@@ -248,3 +248,19 @@ export function commonPath(paths: string[], sep = "/"): string {
   const prefix = parts.slice(0, endOfPrefix).join(sep);
   return prefix.endsWith(sep) ? prefix : `${prefix}${sep}`;
 }
+
+/** Utility function to turn the number of bytes into a human readable
+ * unit */
+export function humanFileSize(bytes: number): string {
+  const thresh = 1000;
+  if (Math.abs(bytes) < thresh) {
+    return bytes + " B";
+  }
+  const units = ["kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"];
+  let u = -1;
+  do {
+    bytes /= thresh;
+    ++u;
+  } while (Math.abs(bytes) >= thresh && u < units.length - 1);
+  return `${bytes.toFixed(1)} ${units[u]}`;
+}

cli/tests/bundle.test.out

@@ -14,5 +14,9 @@ define("mod1", ["require", "exports", "subdir2/mod2"], function (require, export
 [WILDCARD]
 });
 
-instantiate(["mod1"]);
+const __rootExports = instantiate("mod1");
+export const returnsHi = __rootExports["returnsHi"];
+export const returnsFoo2 = __rootExports["returnsFoo2"];
+export const printHello3 = __rootExports["printHello3"];
+export const throwsError = __rootExports["throwsError"];
 

cli/tests/integration_tests.rs

@@ -55,6 +55,47 @@ fn js_unit_tests() {
   drop(g);
 }
 
+#[test]
+fn bundle_exports() {
+  use tempfile::TempDir;
+
+  // First we have to generate a bundle of some module that has exports.
+  let mod1 = util::root_path().join("cli/tests/subdir/mod1.ts");
+  assert!(mod1.is_file());
+  let t = TempDir::new().expect("tempdir fail");
+  let bundle = t.path().join("mod1.bundle.js");
+  let mut deno = util::deno_cmd()
+    .current_dir(util::root_path())
+    .arg("bundle")
+    .arg(mod1)
+    .arg(&bundle)
+    .spawn()
+    .expect("failed to spawn script");
+  let status = deno.wait().expect("failed to wait for the child process");
+  assert!(status.success());
+  assert!(bundle.is_file());
+
+  // Now we try to use that bundle from another module.
+  let test = t.path().join("test.js");
+  std::fs::write(
+    &test,
+    "
+      import { printHello3 } from \"./mod1.bundle.js\";
+      printHello3(); ",
+  )
+  .expect("error writing file");
+
+  let output = util::deno_cmd()
+    .current_dir(util::root_path())
+    .arg("run")
+    .arg(&test)
+    .output()
+    .expect("failed to spawn script");
+  // check the output of the test.ts program.
+  assert_eq!(std::str::from_utf8(&output.stdout).unwrap().trim(), "Hello");
+  assert_eq!(output.stderr, b"");
+}
+
 // TODO(#2933): Rewrite this test in rust.
 #[test]
 fn repl_test() {

deno_typescript/bundle_loader.js

@@ -6,14 +6,16 @@
 // bundles when creating snapshots, but is also used when emitting bundles from
 // Deno cli.
 
+// @ts-nocheck
+
 /**
- * @type {(name: string, deps: ReadonlyArray<string>, factory: (...deps: any[]) => void) => void}
+ * @type {(name: string, deps: ReadonlyArray<string>, factory: (...deps: any[]) => void) => void=}
  */
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 let define;
 
 /**
- * @type {(mod: string | string[]) => void}
+ * @type {(mod: string) => any=}
  */
 // eslint-disable-next-line @typescript-eslint/no-unused-vars
 let instantiate;
@@ -111,14 +113,9 @@ let instantiate;
 
   instantiate = dep => {
     define = undefined;
-    if (Array.isArray(dep)) {
-      for (const d of dep) {
-        getExports(d);
-      }
-    } else {
-      getExports(dep);
-    }
+    const result = getExports(dep);
     // clean up, or otherwise these end up in the runtime environment
     instantiate = undefined;
+    return result;
   };
 })();

std/manual.md

@@ -797,27 +797,50 @@ Particularly useful ones:
 dependencies of the specified input. For example:
 
 ```
-> deno bundle https://deno.land/std/examples/colors.ts
+> deno bundle https://deno.land/std/examples/colors.ts colors.bundle.js
 Bundling "colors.bundle.js"
 Emitting bundle to "colors.bundle.js"
 9.2 kB emitted.
 ```
 
+If you omit the out file, the bundle will be sent to `stdout`.
+
 The bundle can just be run as any other module in Deno would:
 
 ```
 deno colors.bundle.js
 ```
 
-Bundles can also be loaded in the web browser. For example:
+The output is a self contained ES Module, which any exports from the main module
+supplied on the command line will be available. For example if the main module
+looked something like this:
+
+```ts
+export { foo } from "./foo.js";
+
+export const bar = "bar";
+```
+
+It could be imported like this:
+
+```ts
+import { foo, bar } from "./lib.bundle.js";
+```
+
+Bundles can also be loaded in the web browser. The bundle is a self-contained ES
+module, and so the attribute of `type` must be set to `"module"`. For example:
 
 ```html
-<script src="website.bundle.js"></script>
+<script type="module" src="website.bundle.js"></script>
 ```
 
-Bundles, whether loaded in the web browser, or in Deno, would run the root
-module which is specified on the command line when creating the bundle, so put
-any initiation logic in that module.
+Or you could import it into another ES module to consume:
+
+```html
+<script type="module">
+  import * as website from "website.bundle.js";
+</script>
+```
 
 ### Installing executable scripts