allow local data to override globals

src/generate/createGenerator.js

@@ -131,22 +131,31 @@ export default function createGenerator ( parsed, source, names ) {
 
 						if ( parent && parent.type === 'CallExpression' && node === parent.callee && generator.helpers[ name ] ) {
 							generator.code.prependRight( node.start, `template.helpers.` );
-							return;
 						}
 
-						if ( name === 'event' && isEventHandler ) {
-							return;
+						else if ( name === 'event' && isEventHandler ) {
+							// noop
 						}
 
-						if ( contexts[ name ] ) {
+						else if ( contexts[ name ] ) {
 							dependencies.push( ...contextDependencies[ name ] );
 							if ( !~usedContexts.indexOf( name ) ) usedContexts.push( name );
-						} else if ( indexes[ name ] ) {
+						}
+
+						else if ( indexes[ name ] ) {
 							const context = indexes[ name ];
 							if ( !~usedContexts.indexOf( context ) ) usedContexts.push( context );
-						} else if ( !globalWhitelist[ name ] ) {
+						}
+
+						else {
+							if ( globalWhitelist[ name ] ) {
+								generator.code.prependRight( node.start, `( '${name}' in root ? root.` );
+								generator.code.appendLeft( node.object.end, ` : ${name} )` );
+							} else {
+								generator.code.prependRight( node.start, `root.` );
+							}
+
 							dependencies.push( name );
-							generator.code.prependRight( node.start, `root.` );
 							if ( !~usedContexts.indexOf( 'root' ) ) usedContexts.push( 'root' );
 						}
 

test/generator/globals-shadowed-by-data/_config.js

@@ -0,0 +1,12 @@
+export default {
+	data: {
+		x: 10
+	},
+
+	html: 'potato',
+
+	test ( assert, component, target ) {
+		component.set({ x: 3 });
+		assert.htmlEqual( target.innerHTML, 'potato' );
+	}
+};

test/generator/globals-shadowed-by-data/main.html

@@ -0,0 +1,15 @@
+{{Math.min(x, 5)}}
+
+<script>
+	export default {
+		data () {
+			return {
+				Math: {
+					min ( a, b ) {
+						return 'potato';
+					}
+				}
+			};
+		}
+	};
+</script>

test/generator/globals-shadowed-by-helpers/_config.js

@@ -0,0 +1,12 @@
+export default {
+	data: {
+		x: 10
+	},
+
+	html: 'potato',
+
+	test ( assert, component, target ) {
+		component.set({ x: 3 });
+		assert.htmlEqual( target.innerHTML, 'potato' );
+	}
+};

test/generator/globals-shadowed-by-helpers/main.html

@@ -0,0 +1,13 @@
+{{Math.min(x, 5)}}
+
+<script>
+	export default {
+		helpers: {
+			Math: {
+				min ( a, b ) {
+					return 'potato';
+				}
+			}
+		}
+	};
+</script>