refactor and robustify export blocks

src/finalisers/amd.js

@@ -1,5 +1,6 @@
 import { getName, quoteId } from '../utils/map-helpers';
 import getInteropBlock from './shared/getInteropBlock';
+import getExportBlock from './shared/getExportBlock';
 
 export default function amd ( bundle, magicString, { exportMode, indentString }, options ) {
 	let deps = bundle.externalModules.map( quoteId );
@@ -20,18 +21,7 @@ export default function amd ( bundle, magicString, { exportMode, indentString },
 	const interopBlock = getInteropBlock( bundle );
 	if ( interopBlock ) magicString.prepend( interopBlock + '\n\n' );
 
-	const exports = bundle.entryModule.exports;
-
-	let exportBlock;
-
-	if ( exportMode === 'default' ) {
-		exportBlock = `return ${bundle.entryModule.getCanonicalName('default')};`;
-	} else {
-		exportBlock = bundle.toExport.map( name => {
-			return `exports.${name} = ${exports[name].localName};`;
-		}).join( '\n' );
-	}
-
+	const exportBlock = getExportBlock( bundle, exportMode );
 	if ( exportBlock ) magicString.append( '\n\n' + exportBlock );
 
 	return magicString

src/finalisers/cjs.js

@@ -1,3 +1,5 @@
+import getExportBlock from './shared/getExportBlock';
+
 export default function cjs ( bundle, magicString, { exportMode }) {
 	let intro = `'use strict';\n\n`;
 
@@ -21,23 +23,8 @@ export default function cjs ( bundle, magicString, { exportMode }) {
 
 	magicString.prepend( intro );
 
-	let exportBlock;
-	if ( exportMode === 'default' && bundle.entryModule.exports.default ) {
-		exportBlock = `module.exports = ${bundle.entryModule.getCanonicalName('default')};`;
-	} else if ( exportMode === 'named' ) {
-		exportBlock = bundle.toExport
-			.map( key => {
-				const specifier = bundle.entryModule.exports[ key ];
-				const name = bundle.entryModule.getCanonicalName( specifier.localName );
-
-				return `exports.${key} = ${name};`;
-			})
-			.join( '\n' );
-	}
-
-	if ( exportBlock ) {
-		magicString.append( '\n\n' + exportBlock );
-	}
+	const exportBlock = getExportBlock( bundle, exportMode, 'module.exports =' );
+	if ( exportBlock ) magicString.append( '\n\n' + exportBlock );
 
 	return magicString;
 }

src/finalisers/iife.js

@@ -1,6 +1,7 @@
 import { blank } from '../utils/object';
 import { getName } from '../utils/map-helpers';
 import getInteropBlock from './shared/getInteropBlock';
+import getExportBlock from './shared/getExportBlock';
 
 export default function iife ( bundle, magicString, { exportMode, indentString }, options ) {
 	const globalNames = options.globals || blank();
@@ -23,16 +24,16 @@ export default function iife ( bundle, magicString, { exportMode, indentString }
 	let intro = `(function (${args}) { 'use strict';\n\n`;
 	let outro = `\n\n})(${dependencies});`;
 
-	// var foo__default = 'default' in foo ? foo['default'] : foo;
-	const interopBlock = getInteropBlock( bundle );
-	if ( interopBlock ) magicString.prepend( interopBlock + '\n\n' );
-
 	if ( exportMode === 'default' ) {
 		intro = `var ${options.moduleName} = ${intro}`;
-		magicString.append( `\n\nreturn ${bundle.entryModule.getCanonicalName('default')};` );
 	}
 
-	// TODO named exports
+	// var foo__default = 'default' in foo ? foo['default'] : foo;
+	const interopBlock = getInteropBlock( bundle );
+	if ( interopBlock ) magicString.prepend( interopBlock + '\n\n' );
+
+	const exportBlock = getExportBlock( bundle, exportMode );
+	if ( exportBlock ) magicString.append( '\n\n' + exportBlock );
 
 	return magicString
 		.indent( indentString )

src/finalisers/shared/getExportBlock.js

@@ -0,0 +1,12 @@
+export default function getExportBlock ( bundle, exportMode, mechanism = 'return' ) {
+	if ( exportMode === 'default' ) {
+		return `${mechanism} ${bundle.entryModule.getCanonicalName('default')};`;
+	}
+
+	return bundle.toExport
+		.map( name => {
+			const prop = name === 'default' ? `['default']` : `.${name}`;
+			return `exports${prop} = ${bundle.entryModule.getCanonicalName(name)};`;
+		})
+		.join( '\n' );
+}

src/finalisers/umd.js

@@ -1,6 +1,7 @@
 import { blank } from '../utils/object';
 import { getName, quoteId, req } from '../utils/map-helpers';
 import getInteropBlock from './shared/getInteropBlock';
+import getExportBlock from './shared/getExportBlock';
 
 export default function umd ( bundle, magicString, { exportMode, indentString }, options ) {
 	if ( exportMode !== 'none' && !options.moduleName ) {
@@ -45,23 +46,8 @@ export default function umd ( bundle, magicString, { exportMode, indentString },
 	const interopBlock = getInteropBlock( bundle );
 	if ( interopBlock ) magicString.prepend( interopBlock + '\n\n' );
 
-	const exports = bundle.entryModule.exports;
-
-	let exportBlock;
-
-	if ( exportMode === 'default' ) {
-		const canonicalName = bundle.entryModule.getCanonicalName( 'default' );
-		exportBlock = `return ${canonicalName};`;
-	} else {
-		exportBlock = bundle.toExport.map( name => {
-			const canonicalName = bundle.entryModule.getCanonicalName( exports[ name ].localName );
-			return `exports.${name} = ${canonicalName};`;
-		}).join( '\n' );
-	}
-
-	if ( exportBlock ) {
-		magicString.append( '\n\n' + exportBlock );
-	}
+	const exportBlock = getExportBlock( bundle, exportMode );
+	if ( exportBlock ) magicString.append( '\n\n' + exportBlock );
 
 	return magicString
 		.trim()