replace names as necessary

src/Bundle/index.js

@@ -91,63 +91,9 @@ export default class Bundle {
 
 		return {
 			code: magicString.toString(),
-			map: null // TODO use magicString.generateMap()
-		};
-
-		// try {
-			// const code = generate({
-			// 	type: 'Program',
-			// 	body: this.body
-			// });
-
-			// const code = this.body.map( statement => statement._source.toString ).join( '\n' );
-
-			// return {
-			// 	code,
-			// 	map: null // TODO...
-			// };
-		// } catch ( err ) {
-		// 	// probably an escodegen error
-		// 	console.log( 'this.body', this.body );
-		// 	console.log( 'err.stack', err.stack );
-		// 	throw err;
-		// }
-	}
-
-	getName ( module, localName ) {
-		if ( !hasOwnProp.call( this.names, module.path ) ) {
-			this.names[ module.path ] = {};
-		}
-
-		const moduleNames = this.names[ module.path ];
-
-		if ( !moduleNames ) {
-			throw new Error( `Could not get name for ${module.relativePath}:${localName}` );
-		}
-
-		return moduleNames[ localName ];
-	}
-
-	suggestName ( module, localName, globalName ) {
-		if ( !hasOwnProp.call( this.names, module.path ) ) {
-			this.names[ module.path ] = {};
-		}
-
-		const moduleNames = this.names[ module.path ];
-
-		if ( !hasOwnProp.call( moduleNames, globalName ) ) {
-			const relativePathParts = module.relativePath.split( sep );
+			map: magicString.generateMap({
 
-			while ( hasOwnProp.call( this.usedNames, globalName ) && relativePathParts.length ) {
-				globalName = relativePathParts.pop() + `__${globalName}`;
-			}
-
-			while ( hasOwnProp.call( this.usedNames, globalName ) ) {
-				globalName = `_${globalName}`;
-			}
-
-			this.usedNames[ globalName ] = true;
-			moduleNames[ localName ] = globalName;
-		}
+			})
+		};
 	}
 }

src/Module/index.js

@@ -5,6 +5,7 @@ import MagicString from 'magic-string';
 import analyse from '../ast/analyse';
 import { hasOwnProp } from '../utils/object';
 import { sequence } from '../utils/promise';
+import replaceIdentifiers from '../utils/replaceIdentifiers';
 
 const emptyArrayPromise = Promise.resolve([]);
 
@@ -20,9 +21,9 @@ export default class Module {
 			sourceType: 'module'
 		});
 
-		console.log( '\nanalysing %s\n========', path );
 		analyse( this.ast, this.code );
-		console.log( '========\n\n' );
+
+		this.nameReplacements = {};
 
 		this.definitions = {};
 		this.definitionPromises = {};
@@ -34,7 +35,11 @@ export default class Module {
 			});
 
 			Object.keys( statement._modifies ).forEach( name => {
-				this.modifications[ name ] = statement;
+				if ( !hasOwnProp.call( this.modifications, name ) ) {
+					this.modifications[ name ] = [];
+				}
+
+				this.modifications[ name ].push( statement );
 			});
 		});
 
@@ -62,8 +67,8 @@ export default class Module {
 
 				this.exports.default = {
 					node,
-					localName: 'default',
-					name: isDeclaration ? node.declaration.id.name : null,
+					name: 'default',
+					localName: isDeclaration ? node.declaration.id.name : 'default',
 					isDeclaration
 				};
 			}
@@ -128,7 +133,7 @@ export default class Module {
 						// we 'suggest' that the bundle use our local name for this import
 						// throughout the bundle. If that causes a conflict, we'll end up
 						// with something slightly different
-						this.bundle.suggestName( module, exportDeclaration.localName, importDeclaration.localName );
+						module.nameReplacements[ exportDeclaration.localName ] = importDeclaration.localName;
 
 						return module.define( exportDeclaration.localName );
 					});
@@ -137,22 +142,27 @@ export default class Module {
 			// The definition is in this module
 			else if ( name === 'default' && this.exports.default.isDeclaration ) {
 				// We have something like `export default foo` - so we just start again,
-				// searching for `foo` instead of default
+				// searching for `foo` instead of default. First, sync up names
+				this.nameReplacements.default = this.exports.default.name;
 				promise = this.define( this.exports.default.name );
 			}
 
 			else {
 				let statement;
 
+				if ( !name ) {
+					console.log( new Error( 'no name' ).stack );
+				}
+
 				if ( name === 'default' ) {
 					// We have an expression, e.g. `export default 42`. We have
 					// to assign that expression to a variable
-					const name = this.bundle.getName( this, 'default' );
+					const replacement = this.nameReplacements.default;
 
 					statement = this.exports.default.node;
 
 					if ( !statement._imported ) {
-						statement._source.overwrite( statement.start, statement.declaration.start, `var ${name} = ` )
+						statement._source.overwrite( statement.start, statement.declaration.start, `var ${replacement} = ` )
 					}
 				}
 
@@ -167,19 +177,34 @@ export default class Module {
 				if ( statement && !statement._imported ) {
 					const nodes = [];
 
-					promise = sequence( Object.keys( statement._dependsOn ), name => {
-						return this.define( name );
-					})
-						.then( definitions => {
-							definitions.forEach( definition => nodes.push.apply( nodes, definition ) );
-						})
-						.then( () => {
-							statement._imported = true;
-							nodes.push( statement );
-						})
-						.then( () => {
-							return nodes;
-						});
+					// replace identifiers, as necessary
+					replaceIdentifiers( statement, statement._source, this.nameReplacements );
+
+					const include = statement => {
+						if ( statement._imported ) return emptyArrayPromise;
+
+						const dependencies = Object.keys( statement._dependsOn );
+
+						return sequence( dependencies, name => this.define( name ) )
+							.then( definitions => {
+								definitions.forEach( definition => nodes.push.apply( nodes, definition ) );
+							})
+							.then( () => {
+								statement._imported = true;
+								nodes.push( statement );
+
+								const modifications = hasOwnProp.call( this.modifications, name ) && this.modifications[ name ];
+
+								if ( modifications ) {
+									return sequence( modifications, include );
+								}
+							})
+							.then( () => {
+								return nodes;
+							});
+					};
+
+					promise = include( statement );
 				}
 			}
 
@@ -188,4 +213,8 @@ export default class Module {
 
 		return this.definitionPromises[ name ];
 	}
+
+	replaceName ( name, replacement ) {
+		this.nameReplacements[ name ] = replacement;
+	}
 }

src/ast/analyse.js

@@ -9,7 +9,7 @@ function isStatement ( node, parent ) {
 	       node.type === 'FunctionDeclaration'; // TODO or any of the other various statement-ish things it could be
 }
 
-export default function analyse ( ast, code ) {
+export default function analyse ( ast, magicString ) {
 	let scope = new Scope();
 	let topLevelStatements = [];
 	let currentTopLevelStatement;
@@ -44,7 +44,7 @@ export default function analyse ( ast, code ) {
 		statement._imported = false;
 
 		// store the actual code, for easy regeneration
-		statement._source = code.snip( previous, statement.end );
+		statement._source = magicString.snip( previous, statement.end );
 		previous = statement.end;
 
 		currentTopLevelStatement = statement; // so we can attach scoping info
@@ -53,6 +53,8 @@ export default function analyse ( ast, code ) {
 			enter ( node, parent ) {
 				let newScope;
 
+				magicString.addSourcemapLocation( node.start );
+
 				switch ( node.type ) {
 					case 'FunctionExpression':
 					case 'FunctionDeclaration':
@@ -137,7 +139,19 @@ export default function analyse ( ast, code ) {
 		}
 
 		function checkForWrites ( node ) {
+			if ( node.type === 'AssignmentExpression' ) {
+				let assignee = node.left;
+
+				while ( assignee.type === 'MemberExpression' ) {
+					assignee = assignee.object;
+				}
 
+				if ( assignee.type !== 'Identifier' ) { // could be a ThisExpression
+					return;
+				}
+
+				statement._modifies[ assignee.name ] = true;
+			}
 		}
 
 		walk( statement, {

src/rollup.js

@@ -1,6 +1,10 @@
+import { basename } from 'path';
 import { writeFile } from 'sander';
 import Bundle from './Bundle';
 
+let SOURCEMAPPING_URL = 'sourceMa';
+SOURCEMAPPING_URL += 'ppingURL';
+
 export function rollup ( entry, options = {} ) {
 	const bundle = new Bundle({
 		entry,
@@ -11,9 +15,14 @@ export function rollup ( entry, options = {} ) {
 		return {
 			generate: options => bundle.generate( options ),
 			write: ( dest, options ) => {
-				const generated = bundle.generate( options );
+				let { code, map } = bundle.generate( options );
+
+				code += `\n//# ${SOURCEMAPPING_URL}=${basename( dest )}.map`;
 
-				return writeFile( dest, generated.code );
+				return Promise.all([
+					writeFile( dest, code ),
+					writeFile( dest + '.map', map.toString() )
+				]);
 			}
 		};
 	});

src/utils/replaceIdentifiers.js

@@ -0,0 +1,55 @@
+import walk from '../ast/walk';
+import { hasOwnProp } from './object';
+
+export default function replaceIdentifiers ( statement, snippet, names ) {
+	const replacementStack = [ names ];
+
+	const keys = Object.keys( names );
+
+	if ( keys.length === 0 ) {
+		return;
+	}
+
+	walk( statement, {
+		enter ( node, parent ) {
+			const scope = node._scope;
+
+			if ( scope ) {
+				let newNames = {};
+				let hasReplacements;
+
+				keys.forEach( key => {
+					if ( !~scope.names.indexOf( key ) ) {
+						newNames[ key ] = names[ key ];
+						hasReplacements = true;
+					}
+				});
+
+				if ( !hasReplacements ) {
+					return this.skip();
+				}
+
+				replacementStack.push( newNames );
+			}
+
+			if ( node.type === 'Identifier' && parent.type !== 'MemberExpression' ) {
+				let name = node.name;
+
+				while ( hasOwnProp.call( names, name ) && name !== names[ name ] ) {
+					name = names[ name ];
+				}
+
+				if ( name && name !== node.name ) {
+					snippet.overwrite( node.start, node.end, name );
+				}
+			}
+		},
+
+		leave ( node ) {
+			if ( node._scope ) {
+				replacementStack.pop();
+				names = replacementStack[ replacementStack.length - 1 ];
+			}
+		}
+	});
+}

test/samples/import-default-as-other/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'imports a default import by another name'
+};

test/samples/import-default-as-other/foo.js

@@ -0,0 +1,3 @@
+export default function foo () {
+	return 42;
+}

test/samples/import-default-as-other/main.js

@@ -0,0 +1,2 @@
+import bar from './foo';
+assert.equal( bar(), 42 );

test/samples/import-named-function-as-other/_config.js

@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'imports a named function by another name'
+};

test/samples/import-named-function-as-other/foo.js

@@ -0,0 +1,3 @@
+export function foo () {
+	return 42;
+}

test/samples/import-named-function-as-other/main.js

@@ -0,0 +1,2 @@
+import { foo as bar } from './foo';
+assert.equal( bar(), 42 );