Merge pull request #32 from rollup/gh-31

rewrite top-level this expressions

src/index.js

@@ -104,9 +104,12 @@ export default function commonjs ( options = {} ) {
 				customNamedExports[ id ].forEach( name => namedExports[ name ] = true );
 			}
 
+			let scopeDepth = 0;
+
 			walk( ast, {
 				enter ( node, parent ) {
 					if ( node.scope ) scope = node.scope;
+					if ( /^Function/.test( node.type ) ) scopeDepth += 1;
 
 					if ( sourceMap ) {
 						magicString.addSourcemapLocation( node.start );
@@ -143,6 +146,12 @@ export default function commonjs ( options = {} ) {
 						return;
 					}
 
+					if ( node.type === 'ThisExpression' && scopeDepth === 0 ) {
+						uses.global = true;
+						magicString.overwrite( node.start, node.end, `__commonjs_global`, true );
+						return;
+					}
+
 					if ( node.type !== 'CallExpression' ) return;
 					if ( node.callee.name !== 'require' || scope.contains( 'require' ) ) return;
 					if ( node.arguments.length !== 1 || node.arguments[0].type !== 'Literal' ) return; // TODO handle these weird cases?
@@ -170,6 +179,7 @@ export default function commonjs ( options = {} ) {
 
 				leave ( node ) {
 					if ( node.scope ) scope = scope.parent;
+					if ( /^Function/.test( node.type ) ) scopeDepth -= 1;
 				}
 			});
 

test/samples/this/foo.js

@@ -0,0 +1,5 @@
+module.exports = function augmentThis () {
+	this.x = 'x';
+};
+
+this.y = 'y';

test/samples/this/main.js

@@ -0,0 +1,7 @@
+var foo = require( './foo' );
+
+var obj = {};
+foo.call( obj );
+
+assert.equal( obj.x, 'x' );
+assert.equal( this.y, 'y' );

test/test.js

@@ -201,4 +201,11 @@ describe( 'rollup-plugin-commonjs', () => {
 			assert.equal( executeBundle( bundle ).exports, 42 );
 		});
 	});
+
+	it.only( 'rewrites top-level this expressions', () => {
+		return rollup({
+			entry: 'samples/this/main.js',
+			plugins: [ commonjs() ]
+		}).then( executeBundle );
+	});
 });