Fix placement of inserted semicolon when using SystemJS (#2529)

* Fix ordering of inserted semicolons

* Update insertion of SystemJS export, revert change to semicolons

src/ast/nodes/AssignmentExpression.ts

@@ -52,7 +52,7 @@ export default class AssignmentExpression extends NodeBase {
 				code.original.indexOf('=', this.left.end) + 1,
 				` exports('${this.left.variable.exportName}',`
 			);
-			code.prependRight(this.right.end, `)`);
+			code.appendLeft(this.right.end, `)`);
 		}
 	}
 }

test/form/samples/modify-export-semi/_config.js

@@ -0,0 +1,4 @@
+module.exports = {
+	description: 'inserts semicolons correctly when modifying SystemJS exports',
+	formats: ['system']
+};

test/form/samples/modify-export-semi/_expected/system.js

@@ -0,0 +1,12 @@
+System.register([], function (exports, module) {
+	'use strict';
+	return {
+		execute: function () {
+
+			let foo = exports('foo', 'foo');
+
+			foo = exports('foo', 'bar');
+
+		}
+	};
+});

test/form/samples/modify-export-semi/main.js

@@ -0,0 +1,3 @@
+export let foo = 'foo'
+
+foo = 'bar'