add aggressive mode

src/Bundle.js

@@ -50,6 +50,7 @@ export default class Bundle {
 
 		this.external = options.external || [];
 		this.onwarn = options.onwarn || onwarn;
+		this.aggressive = options.aggressive;
 
 		// TODO strictly speaking, this only applies with non-ES6, non-default-only bundles
 		[ 'module', 'exports' ].forEach( global => this.assumedGlobals[ global ] = true );
@@ -74,7 +75,11 @@ export default class Bundle {
 				});
 
 				// mark statements that should appear in the bundle
-				this.modules.forEach( module => module.markStatements() );
+				if ( this.aggressive ) {
+					entryModule.markStatements();
+				} else {
+					this.modules.forEach( module => module.markStatements() );
+				}
 
 				this.orderedModules = this.sort();
 				this.deconflict();

test/form/aggressive/_config.js

@@ -0,0 +1,6 @@
+module.exports = {
+	description: 'ignores side-effects outside entry module in aggressive mode',
+	options: {
+		aggressive: true
+	}
+}

test/form/aggressive/_expected/amd.js

@@ -0,0 +1,9 @@
+define(function () { 'use strict';
+
+	function foo () {
+		return 42;
+	}
+
+	assert.equal( foo(), 42 );
+
+});

test/form/aggressive/_expected/cjs.js

@@ -0,0 +1,7 @@
+'use strict';
+
+function foo () {
+	return 42;
+}
+
+assert.equal( foo(), 42 );

test/form/aggressive/_expected/es6.js

@@ -0,0 +1,5 @@
+function foo () {
+	return 42;
+}
+
+assert.equal( foo(), 42 );

test/form/aggressive/_expected/iife.js

@@ -0,0 +1,9 @@
+(function () { 'use strict';
+
+	function foo () {
+		return 42;
+	}
+
+	assert.equal( foo(), 42 );
+
+})();

test/form/aggressive/_expected/umd.js

@@ -0,0 +1,13 @@
+(function (global, factory) {
+	typeof exports === 'object' && typeof module !== 'undefined' ? factory() :
+	typeof define === 'function' && define.amd ? define(factory) :
+	factory();
+}(this, function () { 'use strict';
+
+	function foo () {
+		return 42;
+	}
+
+	assert.equal( foo(), 42 );
+
+}));

test/form/aggressive/foo.js

@@ -0,0 +1,9 @@
+function x () {
+	console.log( 'side-effect' );
+}
+
+x();
+
+export function foo () {
+	return 42;
+}

test/form/aggressive/main.js

@@ -0,0 +1,3 @@
+import { foo } from './foo';
+
+assert.equal( foo(), 42 );