ensure at least one newline between each statement

src/Bundle.js

@@ -240,8 +240,9 @@ export default class Bundle {
 				magicString.addSource( new MagicString( commentBlock ) );
 			}
 
-			// add margin
-			const margin = Math.max( statement.margin[0], previousMargin );
+			// ensure there is always a newline between statements, and add
+			// additional newlines as necessary to reflect original source
+			const margin = Math.max( 2, statement.margin[0], previousMargin );
 			const newLines = new Array( margin ).join( '\n' );
 
 			// add the statement itself

src/Module.js

@@ -43,7 +43,7 @@ export default class Module {
 			});
 
 			this.statements = ast.body.map( node => {
-				const magicString = this.magicString.snip( node.start, node.end ).prepend( '\n' ).append( '\n' );
+				const magicString = this.magicString.snip( node.start, node.end ).trim();
 				return new Statement( node, magicString, this );
 			});
 		} catch ( err ) {

test/function/newline-after-comment/_config.js

@@ -0,0 +1,9 @@
+var assert = require( 'assert' );
+
+module.exports = {
+	description: 'inserts newline after comment',
+	exports: function ( exports ) {
+		assert.equal( exports(), 42 );
+	},
+	// solo: true
+};

test/function/newline-after-comment/main.js

@@ -0,0 +1,4 @@
+// this comment should not affect the line below
+export default function () {
+	return 42;
+}