allow rewrites of variable declarator inits – fixes #632

src/Module.js

@@ -458,13 +458,8 @@ export default class Module {
 					const declaration = this.declarations[ declarator.id.name ];
 
 					if ( declaration.exportName && declaration.isReassigned ) { // `var foo = ...` becomes `exports.foo = ...`
-						if ( declarator.init ) {
-							magicString.overwrite( statement.start, declarator.init.start, `exports.${declaration.exportName} = ` );
-						} else {
-							magicString.remove( statement.start, declarator.init ? declarator.start : statement.next );
-						}
-
-						return;
+						magicString.remove( statement.start, declarator.init ? declarator.start : statement.next );
+						if ( !declarator.init ) return;
 					}
 				}
 

test/function/assignment-to-exports-b/_config.js

@@ -0,0 +1,8 @@
+const assert = require( 'assert' );
+
+module.exports = {
+	description: 'exports are kept up-to-date',
+	exports: exports => {
+		assert.equal( exports.b, 42 );
+	}
+};

test/function/assignment-to-exports-b/main.js

@@ -0,0 +1,9 @@
+var a = { prop: 42 };
+var b = a.prop;
+
+function set ( new_a, new_b ) {
+	a = new_a;
+	b = new_b;
+}
+
+export { a, b, set };