Add bundle loader (denoland/std#480)

Original: denoland/std@fe7f6e1

bundle/README.md

@@ -0,0 +1,16 @@
+# bundle
+
+These are modules that help support bundling with Deno.
+
+## Usage
+
+The main usage is to load and run bundles. For example, to run a bundle named
+`bundle.js` in your current working directory:
+
+```sh
+deno run https://deno.land/std/bundle/run.ts bundle.js
+```
+
+---
+
+Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.

bundle/run.ts

@@ -0,0 +1,11 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+import { evaluate, instantiate, load } from "./utils.ts";
+
+async function main(args: string[]): Promise<void> {
+  const text = await load(args);
+  const result = evaluate(text);
+  instantiate(...result);
+}
+
+main(Deno.args);

bundle/test.ts

@@ -0,0 +1,111 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+import { test } from "../testing/mod.ts";
+import {
+  assert,
+  AssertionError,
+  assertStrictEq,
+  assertThrowsAsync
+} from "../testing/asserts.ts";
+import { assertEquals } from "../testing/pretty.ts";
+import { evaluate, instantiate, load, ModuleMetaData } from "./utils.ts";
+
+/* eslint-disable @typescript-eslint/no-namespace */
+declare global {
+  namespace globalThis {
+    var __results: [string, string] | undefined;
+  }
+}
+/* eslint-enable @typescript-eslint/no-namespace */
+
+const fixture = `
+define("data", [], { "baz": "qat" });
+define("modB", ["require", "exports", "data"], function(require, exports, data) {
+  "use strict";
+  Object.defineProperty(exports, "__esModule", { value: true });
+  exports.foo = "bar";
+  exports.baz = data.baz;
+});
+define("modA", ["require", "exports", "modB"], function(require, exports, modB) {
+  "use strict";
+  Object.defineProperty(exports, "__esModule", { value: true });
+  globalThis.__results = [modB.foo, modB.baz];
+});
+`;
+
+const fixtureQueue = ["data", "modB", "modA"];
+const fixtureModules = new Map<string, ModuleMetaData>();
+fixtureModules.set("data", {
+  dependencies: [],
+  factory: {
+    baz: "qat"
+  },
+  exports: {}
+});
+fixtureModules.set("modB", {
+  dependencies: ["require", "exports", "data"],
+  factory(_require, exports, data): void {
+    "use strict";
+    Object.defineProperty(exports, "__esModule", { value: true });
+    exports.foo = "bar";
+    exports.baz = data.baz;
+  },
+  exports: {}
+});
+fixtureModules.set("modA", {
+  dependencies: ["require", "exports", "modB"],
+  factory(_require, exports, modB): void {
+    "use strict";
+    Object.defineProperty(exports, "__esModule", { value: true });
+    globalThis.__results = [modB.foo, modB.baz];
+  },
+  exports: {}
+});
+
+test(async function loadBundle(): Promise<void> {
+  const result = await load(["", "./bundle/testdata/bundle.js"]);
+  assert(result != null);
+  assert(
+    result.includes(
+      `define("subdir/print_hello", ["require", "exports"], function(`
+    )
+  );
+});
+
+test(async function loadBadArgs(): Promise<void> {
+  await assertThrowsAsync(
+    async (): Promise<void> => {
+      await load(["bundle/test.ts"]);
+    },
+    AssertionError,
+    "Expected exactly two arguments."
+  );
+});
+
+test(async function loadMissingBundle(): Promise<void> {
+  await assertThrowsAsync(
+    async (): Promise<void> => {
+      await load([".", "bad_bundle.js"]);
+    },
+    AssertionError,
+    `Expected "bad_bundle.js" to exist.`
+  );
+});
+
+test(async function evaluateBundle(): Promise<void> {
+  assert(globalThis.define == null, "Expected 'define' to be undefined");
+  const [queue, modules] = evaluate(fixture);
+  assert(globalThis.define == null, "Expected 'define' to be undefined");
+  assertEquals(queue, ["data", "modB", "modA"]);
+  assert(modules.has("modA"));
+  assert(modules.has("modB"));
+  assert(modules.has("data"));
+  assertStrictEq(modules.size, 3);
+});
+
+test(async function instantiateBundle(): Promise<void> {
+  assert(globalThis.__results == null);
+  instantiate(fixtureQueue, fixtureModules);
+  assertEquals(globalThis.__results, ["bar", "qat"]);
+  delete globalThis.__results;
+});

bundle/utils.ts

@@ -0,0 +1,108 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+import { assertStrictEq, assert } from "../testing/asserts.ts";
+import { exists } from "../fs/exists.ts";
+
+export interface DefineFactory {
+  /* eslint-disable-next-line @typescript-eslint/no-explicit-any */
+  (...args: any): object | void;
+}
+
+export interface ModuleMetaData {
+  dependencies: string[];
+  factory?: DefineFactory | object;
+  exports: object;
+}
+
+type Define = (
+  id: string,
+  dependencies: string[],
+  factory: DefineFactory
+) => void;
+
+/* eslint-disable @typescript-eslint/no-namespace */
+declare global {
+  namespace globalThis {
+    var define: Define | undefined;
+  }
+}
+/* eslint-enable @typescript-eslint/no-namespace */
+
+/** Evaluate the bundle, returning a queue of module IDs and their data to
+ * instantiate.
+ */
+export function evaluate(
+  text: string
+): [string[], Map<string, ModuleMetaData>] {
+  const queue: string[] = [];
+  const modules = new Map<string, ModuleMetaData>();
+
+  globalThis.define = function define(
+    id: string,
+    dependencies: string[],
+    factory: DefineFactory
+  ): void {
+    modules.set(id, {
+      dependencies,
+      factory,
+      exports: {}
+    });
+    queue.push(id);
+  };
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  (Deno as any).core.evalContext(text);
+  // Deleting `define()` so it isn't accidentally there when the modules
+  // instantiate.
+  delete globalThis.define;
+
+  return [queue, modules];
+}
+
+/** Drain the queue of module IDs while instantiating the modules. */
+export function instantiate(
+  queue: string[],
+  modules: Map<string, ModuleMetaData>
+): void {
+  let id: string | undefined;
+  while ((id = queue.shift())) {
+    const module = modules.get(id)!;
+    assert(module != null);
+    assert(module.factory != null);
+
+    const dependencies = module.dependencies.map(
+      (id): object => {
+        if (id === "require") {
+          // TODO(kitsonk) support dynamic import by passing a `require()` that
+          // can return a local module or dynamically import one.
+          return (): void => {};
+        } else if (id === "exports") {
+          return module.exports;
+        }
+        const dep = modules.get(id)!;
+        assert(dep != null);
+        return dep.exports;
+      }
+    );
+
+    if (typeof module.factory === "function") {
+      module.factory!(...dependencies);
+    } else if (module.factory) {
+      // when bundling JSON, TypeScript just emits it as an object/array as the
+      // third argument of the `define()`.
+      module.exports = module.factory;
+    }
+    delete module.factory;
+  }
+}
+
+/** Load the bundle and return the contents asynchronously. */
+export async function load(args: string[]): Promise<string> {
+  // TODO(kitsonk) allow loading of remote bundles via fetch.
+  assertStrictEq(args.length, 2, "Expected exactly two arguments.");
+  const [, bundleFileName] = args;
+  assert(
+    await exists(bundleFileName),
+    `Expected "${bundleFileName}" to exist.`
+  );
+  return new TextDecoder().decode(await Deno.readFile(bundleFileName));
+}

test.ts

@@ -2,6 +2,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 import "./archive/tar_test.ts";
 import "./bytes/test.ts";
+import "./bundle/test.ts";
 import "./colors/test.ts";
 import "./datetime/test.ts";
 import "./encoding/test.ts";