handle named functions as default exports

src/Bundle.js

@@ -77,21 +77,34 @@ export default class Bundle {
 		// bring in top-level AST nodes from the entry module
 		return this.fetchModule( this.entryPath, null )
 			.then( entryModule => {
+				const defaultExport = entryModule.exports.default;
+
 				this.entryModule = entryModule;
 
-				if ( entryModule.exports.default ) {
-					let defaultExportName = makeLegalIdentifier( basename( this.entryPath ).slice( 0, -extname( this.entryPath ).length ) );
+				if ( defaultExport ) {
+					// `export default function foo () {...}` -
+					// use the declared name for the export
+					if ( defaultExport.declaredName ) {
+						entryModule.suggestName( 'default', defaultExport.declaredName );
+					}
 
-					let topLevelNames = [];
-					entryModule.statements.forEach( statement => {
-						keys( statement.defines ).forEach( name => topLevelNames.push( name ) );
-					});
+					// `export default a + b` - generate an export name
+					// based on the filename of the entry module
+					else {
+						let defaultExportName = makeLegalIdentifier( basename( this.entryPath ).slice( 0, -extname( this.entryPath ).length ) );
 
-					while ( ~topLevelNames.indexOf( defaultExportName ) ) {
-						defaultExportName = `_${defaultExportName}`;
-					}
+						// deconflict
+						let topLevelNames = [];
+						entryModule.statements.forEach( statement => {
+							keys( statement.defines ).forEach( name => topLevelNames.push( name ) );
+						});
+
+						while ( ~topLevelNames.indexOf( defaultExportName ) ) {
+							defaultExportName = `_${defaultExportName}`;
+						}
 
-					entryModule.suggestName( 'default', defaultExportName );
+						entryModule.suggestName( 'default', defaultExportName );
+					}
 				}
 
 				return entryModule.expandAllStatements( true );

src/Module.js

@@ -98,11 +98,13 @@ export default class Module {
 			// export default 42;
 			if ( node.type === 'ExportDefaultDeclaration' ) {
 				const isDeclaration = /Declaration$/.test( node.declaration.type );
+				const declaredName = isDeclaration && node.declaration.id.name;
 
 				this.exports.default = {
 					statement,
 					name: 'default',
-					localName: isDeclaration ? node.declaration.id.name : 'default',
+					localName: declaredName || 'default',
+					declaredName,
 					isDeclaration
 				};
 			}

test/test.js

@@ -56,7 +56,7 @@ describe( 'rollup', function () {
 			( config.skip ? it.skip : config.solo ? it.only : it )( dir, function () {
 				var options = extend( {}, config.options, {
 					entry: FUNCTION + '/' + dir + '/main.js'
-				})
+				});
 
 				return rollup.rollup( options )
 					.then( function ( bundle ) {