Add SyntheticGlobalDeclaration

src/Declaration.js

@@ -1,7 +1,9 @@
-import { blank, keys } from './utils/object.js';
+import { blank, forOwn, keys } from './utils/object.js';
 import run from './utils/run.js';
 import { SyntheticReference } from './Reference.js';
 
+const use = alias => alias.use();
+
 export default class Declaration {
 	constructor ( node, isParam, statement ) {
 		if ( node ) {
@@ -68,7 +70,7 @@ export default class Declaration {
 		this.isUsed = true;
 		if ( this.statement ) this.statement.mark();
 
-		this.aliases.forEach( alias => alias.use() );
+		this.aliases.forEach( use );
 	}
 }
 
@@ -129,7 +131,44 @@ export class SyntheticDefaultDeclaration {
 
 		if ( this.original ) this.original.use();
 
-		this.aliases.forEach( alias => alias.use() );
+		this.aliases.forEach( use );
+	}
+}
+
+export class SyntheticGlobalDeclaration {
+	constructor ( name ) {
+		this.name = name;
+		this.isExternal = true;
+		this.isGlobal = true;
+		this.isReassigned = false;
+
+		this.aliases = [];
+
+		this.isUsed = false;
+	}
+
+	addAlias ( declaration ) {
+		this.aliases.push( declaration );
+	}
+
+	addReference ( reference ) {
+		reference.declaration = this;
+		if ( reference.isReassignment ) this.isReassigned = true;
+	}
+
+	render () {
+		return this.name;
+	}
+
+	run () {
+		return true;
+	}
+
+	use () {
+		if ( this.isUsed ) return;
+		this.isUsed = true;
+
+		this.aliases.forEach( use );
 	}
 }
 
@@ -210,11 +249,13 @@ export class SyntheticNamespaceDeclaration {
 	}
 
 	use () {
+		// forOwn( this.originals, use );
+
 		keys( this.originals ).forEach( name => {
 			this.originals[ name ].use();
 		});
 
-		this.aliases.forEach( alias => alias.use() );
+		this.aliases.forEach( use );
 	}
 }
 

src/Module.js

@@ -7,7 +7,11 @@ import { basename, extname } from './utils/path.js';
 import getLocation from './utils/getLocation.js';
 import makeLegalIdentifier from './utils/makeLegalIdentifier.js';
 import SOURCEMAPPING_URL from './utils/sourceMappingURL.js';
-import { SyntheticDefaultDeclaration, SyntheticNamespaceDeclaration } from './Declaration.js';
+import {
+	SyntheticDefaultDeclaration,
+	SyntheticGlobalDeclaration,
+	SyntheticNamespaceDeclaration
+} from './Declaration.js';
 import { isFalsy, isTruthy } from './ast/conditions.js';
 import { emptyBlockStatement } from './ast/create.js';
 import extractNames from './ast/extractNames.js';
@@ -624,7 +628,13 @@ export default class Module {
 
 		const exportDeclaration = this.exports[ name ];
 		if ( exportDeclaration ) {
-			return this.trace( exportDeclaration.localName );
+			const name = exportDeclaration.localName;
+			const declaration = this.trace( name );
+
+			if ( declaration ) return declaration;
+
+			this.bundle.assumedGlobals[ name ] = true;
+			return ( this.declarations[ name ] = new SyntheticGlobalDeclaration( name ) );
 		}
 
 		for ( let i = 0; i < this.exportAllModules.length; i += 1 ) {

src/utils/object.js

@@ -1,5 +1,9 @@
-export const keys = Object.keys;
+export const { keys } = Object;
 
 export function blank () {
 	return Object.create( null );
 }
+
+export function forOwn ( object, func ) {
+	Object.keys( object ).forEach( key => func( object[ key ], key ) );
+}