reattach comments, handle var splitting better

src/Bundle.js

@@ -496,7 +496,10 @@ export default class Bundle {
 		let magicString = new MagicString.Bundle({ separator: '\n\n' });
 
 		this.orderedModules.forEach( module => {
-			magicString.addSource( module.render( allBundleExports, format ) );
+			const source = module.render( allBundleExports, format );
+			if ( source.toString().length ) {
+				magicString.addSource( source );
+			}
 		});
 
 		// prepend bundle with internal namespaces

src/Module.js

@@ -539,6 +539,8 @@ export default class Module {
 		});
 
 		let statements = [];
+		let lastChar = 0;
+		let commentIndex = 0;
 
 		ast.body.forEach( node => {
 			// special case - top-level var declarations with multiple declarators
@@ -550,9 +552,9 @@ export default class Module {
 					//const magicString = this.magicString.snip( declarator.start, declarator.end ).trim();
 					const nextDeclarator = node.declarations[ i + 1 ];
 
-					if ( nextDeclarator ) {
-						this.magicString.overwrite( declarator.end, nextDeclarator.start, `;\n${node.kind} ` ); // TODO indentation
-					}
+					// if ( nextDeclarator ) {
+					// 	this.magicString.overwrite( declarator.end, nextDeclarator.start, `;\n${node.kind} ` ); // TODO indentation
+					// }
 
 					const syntheticNode = {
 						type: 'VariableDeclaration',
@@ -562,15 +564,32 @@ export default class Module {
 						declarations: [ declarator ]
 					};
 
-					const statement = new Statement( syntheticNode, this, node.start, node.end ); // TODO this is almost certainly wrong...
+					const start = i === 0 ? node.start : declarator.start;
+					const end = declarator.end;
+
+					const statement = new Statement( syntheticNode, this, start, end ); // TODO this is almost certainly wrong...
 					statements.push( statement );
 				});
+
+				lastChar = node.end; // TODO account for trailing line comment
 			}
 
 			else {
-				const statement = new Statement( node, this, node.start, node.end ); // TODO should be comment start, comment end
-
+				let comment;
+				do {
+					comment = this.comments[ commentIndex ];
+					if ( !comment ) break;
+					if ( comment.start > node.start ) break;
+					commentIndex += 1;
+				} while ( comment.end < lastChar );
+
+				const start = comment ? Math.min( comment.start, node.start ) : node.start;
+				const end = node.end; // TODO account for trailing line comment
+
+				const statement = new Statement( node, this, start, end );
 				statements.push( statement );
+
+				lastChar = end;
 			}
 		});
 

test/form/exported-empty-vars/_expected/es6.js

@@ -1,8 +1,7 @@
 var foo;
 foo = 42;
 
-var bar;
-var baz;
+var bar, baz;
 
 bar = 43;
 baz = 44;

test/form/self-contained-bundle/_expected/amd.js

@@ -8,7 +8,6 @@ define(function () { 'use strict';
 		return 42;
 	}
 
-
 	// comment before 1
 
 	console.log( 1 );

test/form/self-contained-bundle/_expected/cjs.js

@@ -8,7 +8,6 @@ function bar () {
 	return 42;
 }
 
-
 // comment before 1
 
 console.log( 1 );

test/form/self-contained-bundle/_expected/es6.js

@@ -6,7 +6,6 @@ function bar () {
 	return 42;
 }
 
-
 // comment before 1
 
 console.log( 1 );

test/form/self-contained-bundle/_expected/iife.js

@@ -8,7 +8,6 @@
 		return 42;
 	}
 
-
 	// comment before 1
 
 	console.log( 1 );

test/form/self-contained-bundle/_expected/umd.js

@@ -12,7 +12,6 @@
 		return 42;
 	}
 
-
 	// comment before 1
 
 	console.log( 1 );