From 2af3fe3bb6d241d077f216c4bb711c59aa4069d0 Mon Sep 17 00:00:00 2001
From: Benoit Tremblay <trembl.ben@gmail.com>
Date: Tue, 1 May 2018 10:36:43 -0400
Subject: [PATCH] Expose modules as UMD (#453)

---
 .eslintrc.json                         |  3 ++-
 src/Bundler.js                         |  1 +
 src/builtins/prelude.js                | 23 +++++++++++++++++++-
 src/cli.js                             |  3 +++
 src/packagers/JSPackager.js            |  8 ++++++-
 test/integration/entry-point/index.js  |  5 +++++
 test/integration/entry-point/test.html |  3 +++
 test/javascript.js                     | 29 ++++++++++++++++++++++++++
 8 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 test/integration/entry-point/index.js
 create mode 100644 test/integration/entry-point/test.html

diff --git a/.eslintrc.json b/.eslintrc.json
index 34abf94fb76..99af1fe5342 100644
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -11,6 +11,7 @@
     "es6": true
   },
   "globals": {
-    "parcelRequire": true
+    "parcelRequire": true,
+    "define": true
   }
 }
diff --git a/src/Bundler.js b/src/Bundler.js
index 376955b658c..b650280c337 100644
--- a/src/Bundler.js
+++ b/src/Bundler.js
@@ -99,6 +99,7 @@ class Bundler extends EventEmitter {
         options.hmrHostname ||
         (options.target === 'electron' ? 'localhost' : ''),
       detailedReport: options.detailedReport || false,
+      global: options.global,
       autoinstall:
         typeof options.autoinstall === 'boolean'
           ? options.autoinstall
diff --git a/src/builtins/prelude.js b/src/builtins/prelude.js
index 534e4bec1d2..d0026a7ece3 100644
--- a/src/builtins/prelude.js
+++ b/src/builtins/prelude.js
@@ -7,7 +7,7 @@
 // orig method which is the require for previous bundles
 
 // eslint-disable-next-line no-global-assign
-parcelRequire = (function (modules, cache, entry) {
+parcelRequire = (function (modules, cache, entry, globalName) {
   // Save the require from previous bundle to this closure if any
   var previousRequire = typeof parcelRequire === 'function' && parcelRequire;
   var nodeRequire = typeof require === 'function' && require;
@@ -75,6 +75,27 @@ parcelRequire = (function (modules, cache, entry) {
     newRequire(entry[i]);
   }
 
+  if (entry.length) {
+    // Expose entry point to Node, AMD or browser globals
+    // Based on https://github.com/ForbesLindesay/umd/blob/master/template.js
+    var mainExports = newRequire(entry[entry.length - 1]);
+
+    // CommonJS
+    if (typeof exports === "object" && typeof module !== "undefined") {
+      module.exports = mainExports;
+
+    // RequireJS
+    } else if (typeof define === "function" && define.amd) {
+     define(function () {
+       return mainExports;
+     });
+
+    // <script>
+    } else if (globalName) {
+      this[globalName] = mainExports;
+    }
+  }
+
   // Override the current require with this new one
   return newRequire;
 })
diff --git a/src/cli.js b/src/cli.js
index ec51fd94263..475cef421c8 100755
--- a/src/cli.js
+++ b/src/cli.js
@@ -41,6 +41,7 @@ program
     '--public-url <url>',
     'set the public URL to serve on. defaults to the same as the --out-dir option'
   )
+  .option('--global <variable>', 'expose your module through a global variable')
   .option('--no-hmr', 'disable hot module replacement')
   .option('--no-cache', 'disable the filesystem cache')
   .option('--no-source-maps', 'disable sourcemaps')
@@ -73,6 +74,7 @@ program
     '--public-url <url>',
     'set the public URL to serve on. defaults to the same as the --out-dir option'
   )
+  .option('--global <variable>', 'expose your module through a global variable')
   .option(
     '--hmr-port <port>',
     'set the port to serve HMR websockets, defaults to random',
@@ -113,6 +115,7 @@ program
     '--public-url <url>',
     'set the public URL to serve on. defaults to the same as the --out-dir option'
   )
+  .option('--global <variable>', 'expose your module through a global variable')
   .option('--no-minify', 'disable minification')
   .option('--no-cache', 'disable the filesystem cache')
   .option('--no-source-maps', 'disable sourcemaps')
diff --git a/src/packagers/JSPackager.js b/src/packagers/JSPackager.js
index 7234e66664e..20497de0a28 100644
--- a/src/packagers/JSPackager.js
+++ b/src/packagers/JSPackager.js
@@ -203,7 +203,13 @@ class JSPackager extends Packager {
       entry.push(this.bundle.entryAsset.id);
     }
 
-    await this.write('},{},' + JSON.stringify(entry) + ')');
+    await this.dest.write(
+      '},{},' +
+        JSON.stringify(entry) +
+        ', ' +
+        JSON.stringify(this.options.global || null) +
+        ')'
+    );
     if (this.options.sourceMaps) {
       // Add source map url if a map bundle exists
       let mapBundle = this.bundle.siblingBundlesMap.get('map');
diff --git a/test/integration/entry-point/index.js b/test/integration/entry-point/index.js
new file mode 100644
index 00000000000..f7fd165b707
--- /dev/null
+++ b/test/integration/entry-point/index.js
@@ -0,0 +1,5 @@
+function test() {
+  return 'Test!';
+}
+
+module.exports = test;
diff --git a/test/integration/entry-point/test.html b/test/integration/entry-point/test.html
new file mode 100644
index 00000000000..08942d7f1b1
--- /dev/null
+++ b/test/integration/entry-point/test.html
@@ -0,0 +1,3 @@
+<html>
+<script src="dist/index.js"></script>
+</html>
diff --git a/test/javascript.js b/test/javascript.js
index c9a9c8bb997..c05d3a704a4 100644
--- a/test/javascript.js
+++ b/test/javascript.js
@@ -834,4 +834,33 @@ describe('javascript', function() {
 
     assert.equal(failed, false);
   });
+
+  it('should expose to CommonJS entry point', async function() {
+    let b = await bundle(__dirname + '/integration/entry-point/index.js');
+
+    let module = {};
+    run(b, {module, exports: {}});
+    assert.equal(module.exports(), 'Test!');
+  });
+
+  it('should expose to RequireJS entry point', async function() {
+    let b = await bundle(__dirname + '/integration/entry-point/index.js');
+    let test;
+    const mockDefine = function(f) {
+      test = f();
+    };
+    mockDefine.amd = true;
+
+    run(b, {define: mockDefine});
+    assert.equal(test(), 'Test!');
+  });
+
+  it('should expose variable with --browser-global', async function() {
+    let b = await bundle(__dirname + '/integration/entry-point/index.js', {
+      global: 'testing'
+    });
+
+    const ctx = run(b, null, {require: false});
+    assert.equal(ctx.window.testing(), 'Test!');
+  });
 });