push analyse logic into Statement class

src/Bundle.js

@@ -44,10 +44,10 @@ export default class Bundle {
 
 				if ( !has( this.modulePromises, path ) ) {
 					this.modulePromises[ path ] = readFile( path, { encoding: 'utf-8' })
-						.then( code => {
+						.then( source => {
 							const module = new Module({
 								path,
-								code,
+								source,
 								bundle: this
 							});
 
@@ -67,7 +67,13 @@ export default class Bundle {
 
 				if ( entryModule.exports.default ) {
 					let defaultExportName = makeLegalIdentifier( basename( this.entryPath ).slice( 0, -extname( this.entryPath ).length ) );
-					while ( entryModule.scope.contains( defaultExportName ) ) {
+
+					let topLevelNames = [];
+					entryModule.statements.forEach( statement => {
+						keys( statement.defines ).forEach( name => topLevelNames.push( name ) );
+					});
+
+					while ( ~topLevelNames.indexOf( defaultExportName ) ) {
 						defaultExportName = `_${defaultExportName}`;
 					}
 
@@ -161,7 +167,7 @@ export default class Bundle {
 					}
 				});
 
-			const source = statement.source.clone().trim();
+			const source = statement.magicString.clone().trim();
 
 			// modify exports as necessary
 			if ( /^Export/.test( statement.node.type ) ) {

src/Module.js

@@ -6,39 +6,47 @@ import Statement from './Statement';
 import analyse from './ast/analyse';
 import { has, keys } from './utils/object';
 import { sequence } from './utils/promise';
+import { isImportDeclaration, isExportDeclaration } from './utils/map-helpers';
 import getLocation from './utils/getLocation';
 import makeLegalIdentifier from './utils/makeLegalIdentifier';
 
 const emptyArrayPromise = Promise.resolve([]);
 
 export default class Module {
-	constructor ({ path, code, bundle }) {
+	constructor ({ path, source, bundle }) {
+		this.source = source;
+
 		this.bundle = bundle;
 		this.path = path;
 		this.relativePath = relative( bundle.base, path ).slice( 0, -3 ); // remove .js
 
-		this.code = new MagicString( code, {
+		this.magicString = new MagicString( source, {
 			filename: path
 		});
 
 		this.suggestedNames = {};
 		this.comments = [];
 
+		// Try to extract a list of top-level statements/declarations. If
+		// the parse fails, attach file info and abort
 		try {
-			this.ast = parse( code, {
+			const ast = parse( source, {
 				ecmaVersion: 6,
 				sourceType: 'module',
 				onComment: ( block, text, start, end ) => this.comments.push({ block, text, start, end })
 			});
+
+			this.statements = ast.body.map( node => {
+				const magicString = this.magicString.snip( node.start, node.end );
+				return new Statement( node, magicString, this );
+			});
 		} catch ( err ) {
 			err.file = path;
 			throw err;
 		}
 
-		this.statements = this.ast.body.map( node => {
-			const source = this.code.snip( node.start, node.end );
-			return new Statement( node, source, this );
-		});
+		this.importDeclarations = this.statements.filter( isImportDeclaration );
+		this.exportDeclarations = this.statements.filter( isExportDeclaration );
 
 		this.analyse();
 	}
@@ -48,110 +56,99 @@ export default class Module {
 		this.imports = {};
 		this.exports = {};
 
-		this.statements.forEach( statement => {
+		this.importDeclarations.forEach( statement => {
 			const node = statement.node;
-			let source;
+			const source = node.source.value;
 
-			// import foo from './foo';
-			// import { bar } from './bar';
-			if ( node.type === 'ImportDeclaration' ) {
-				source = node.source.value;
+			node.specifiers.forEach( specifier => {
+				const isDefault = specifier.type === 'ImportDefaultSpecifier';
+				const isNamespace = specifier.type === 'ImportNamespaceSpecifier';
 
-				node.specifiers.forEach( specifier => {
-					const isDefault = specifier.type === 'ImportDefaultSpecifier';
-					const isNamespace = specifier.type === 'ImportNamespaceSpecifier';
+				const localName = specifier.local.name;
+				const name = isDefault ? 'default' : isNamespace ? '*' : specifier.imported.name;
 
-					const localName = specifier.local.name;
-					const name = isDefault ? 'default' : isNamespace ? '*' : specifier.imported.name;
+				if ( has( this.imports, localName ) ) {
+					const err = new Error( `Duplicated import '${localName}'` );
+					err.file = this.path;
+					err.loc = getLocation( this.source, specifier.start );
+					throw err;
+				}
 
-					if ( has( this.imports, localName ) ) {
-						const err = new Error( `Duplicated import '${localName}'` );
-						err.file = this.path;
-						err.loc = getLocation( this.code.original, specifier.start );
-						throw err;
-					}
+				this.imports[ localName ] = {
+					source,
+					name,
+					localName
+				};
+			});
+		});
 
-					this.imports[ localName ] = {
-						source,
-						name,
-						localName
-					};
-				});
+		this.exportDeclarations.forEach( statement => {
+			const node = statement.node;
+			const source = node.source && node.source.value;
+
+			// export default function foo () {}
+			// export default foo;
+			// export default 42;
+			if ( node.type === 'ExportDefaultDeclaration' ) {
+				const isDeclaration = /Declaration$/.test( node.declaration.type );
+
+				this.exports.default = {
+					statement,
+					name: 'default',
+					localName: isDeclaration ? node.declaration.id.name : 'default',
+					isDeclaration
+				};
 			}
 
-			else if ( /^Export/.test( node.type ) ) {
-				// export default function foo () {}
-				// export default foo;
-				// export default 42;
-				if ( node.type === 'ExportDefaultDeclaration' ) {
-					const isDeclaration = /Declaration$/.test( node.declaration.type );
-
-					this.exports.default = {
-						node, // TODO remove this
-						statement,
-						name: 'default',
-						localName: isDeclaration ? node.declaration.id.name : 'default',
-						isDeclaration
-					};
-				}
-
-				// export { foo, bar, baz }
-				// export var foo = 42;
-				// export function foo () {}
-				else if ( node.type === 'ExportNamedDeclaration' ) {
-					// export { foo } from './foo';
-					source = node.source && node.source.value;
-
-					if ( node.specifiers.length ) {
-						// export { foo, bar, baz }
-						node.specifiers.forEach( specifier => {
-							const localName = specifier.local.name;
-							const exportedName = specifier.exported.name;
+			// export { foo, bar, baz }
+			// export var foo = 42;
+			// export function foo () {}
+			else if ( node.type === 'ExportNamedDeclaration' ) {
+				if ( node.specifiers.length ) {
+					// export { foo, bar, baz }
+					node.specifiers.forEach( specifier => {
+						const localName = specifier.local.name;
+						const exportedName = specifier.exported.name;
+
+						this.exports[ exportedName ] = {
+							localName,
+							exportedName
+						};
 
-							this.exports[ exportedName ] = {
+						// export { foo } from './foo';
+						if ( source ) {
+							this.imports[ localName ] = {
+								source,
 								localName,
-								exportedName
+								name: exportedName
 							};
+						}
+					});
+				}
 
-							if ( source ) {
-								this.imports[ localName ] = {
-									source,
-									localName,
-									name: exportedName
-								};
-							}
-						});
-					}
-
-					else {
-						let declaration = node.declaration;
-
-						let name;
+				else {
+					let declaration = node.declaration;
 
-						if ( declaration.type === 'VariableDeclaration' ) {
-							// export var foo = 42
-							name = declaration.declarations[0].id.name;
-						} else {
-							// export function foo () {}
-							name = declaration.id.name;
-						}
+					let name;
 
-						this.exports[ name ] = {
-							node, // TODO remove
-							statement,
-							localName: name,
-							expression: declaration
-						};
+					if ( declaration.type === 'VariableDeclaration' ) {
+						// export var foo = 42
+						name = declaration.declarations[0].id.name;
+					} else {
+						// export function foo () {}
+						name = declaration.id.name;
 					}
+
+					this.exports[ name ] = {
+						statement,
+						localName: name,
+						expression: declaration
+					};
 				}
 			}
 		});
 
-
-
-		analyse( this.ast, this.code, this );
-
-		this.definedNames = this.scope.names.slice(); // TODO is this used?
+		analyse( this.magicString, this );
 
 		this.canonicalNames = {};
 

src/Statement.js

@@ -1,11 +1,16 @@
-import { keys } from './utils/object';
+import { has, keys } from './utils/object';
+import { getName } from './utils/map-helpers';
+import getLocation from './utils/getLocation';
+import walk from './ast/walk';
+import Scope from './ast/Scope';
 
 export default class Statement {
-	constructor ( node, source, module ) {
+	constructor ( node, magicString, module ) {
 		this.node = node;
 		this.module = module;
-		this.source = source;
+		this.magicString = magicString;
 
+		this.scope = new Scope();
 		this.defines = {};
 		this.modifies = {};
 		this.dependsOn = {};
@@ -15,5 +20,168 @@ export default class Statement {
 		this.leadingComments = []
 		this.trailingComment = null;
 		this.margin = [ 0, 0 ];
+
+		// some facts about this statement...
+		this.isImportDeclaration = node.type === 'ImportDeclaration';
+		this.isExportDeclaration = /^Export/.test( node.type );
+	}
+
+	analyse () {
+		if ( this.isImportDeclaration ) return; // nothing to analyse
+
+		const statement = this; // TODO use arrow functions instead
+		const magicString = this.magicString;
+
+		let scope = this.scope;
+
+		function addToScope ( declarator ) {
+			var name = declarator.id.name;
+			scope.add( name, false );
+
+			if ( !scope.parent ) {
+				statement.defines[ name ] = true;
+			}
+		}
+
+		function addToBlockScope ( declarator ) {
+			var name = declarator.id.name;
+			scope.add( name, true );
+
+			if ( !scope.parent ) {
+				statement.defines[ name ] = true;
+			}
+		}
+
+		walk( this.node, {
+			enter ( node ) {
+				let newScope;
+
+				magicString.addSourcemapLocation( node.start );
+
+				switch ( node.type ) {
+					case 'FunctionExpression':
+					case 'FunctionDeclaration':
+					case 'ArrowFunctionExpression':
+						let names = node.params.map( getName );
+
+						if ( node.type === 'FunctionDeclaration' ) {
+							addToScope( node );
+						} else if ( node.type === 'FunctionExpression' && node.id ) {
+							names.push( node.id.name );
+						}
+
+						newScope = new Scope({
+							parent: scope,
+							params: names, // TODO rest params?
+							block: false
+						});
+
+						break;
+
+					case 'BlockStatement':
+						newScope = new Scope({
+							parent: scope,
+							block: true
+						});
+
+						break;
+
+					case 'CatchClause':
+						newScope = new Scope({
+							parent: scope,
+							params: [ node.param.name ],
+							block: true
+						});
+
+						break;
+
+					case 'VariableDeclaration':
+						node.declarations.forEach( node.kind === 'let' ? addToBlockScope : addToScope ); // TODO const?
+						break;
+
+					case 'ClassDeclaration':
+						addToScope( node );
+						break;
+				}
+
+				if ( newScope ) {
+					Object.defineProperty( node, '_scope', { value: newScope });
+					scope = newScope;
+				}
+			},
+			leave ( node ) {
+				if ( node._scope ) {
+					scope = scope.parent;
+				}
+			}
+		});
+
+		if ( !this.isImportDeclaration ) {
+			walk( this.node, {
+				enter: ( node, parent ) => {
+					if ( node._scope ) scope = node._scope;
+
+					this.checkForReads( scope, node, parent );
+					this.checkForWrites( scope, node );
+				},
+				leave: ( node ) => {
+					if ( node._scope ) scope = scope.parent;
+				}
+			});
+		}
+	}
+
+	checkForReads ( scope, node, parent ) {
+		if ( node.type === 'Identifier' ) {
+			// disregard the `bar` in `foo.bar` - these appear as Identifier nodes
+			if ( parent.type === 'MemberExpression' && node !== parent.object ) {
+				return;
+			}
+
+			// disregard the `bar` in { bar: foo }
+			if ( parent.type === 'Property' && node !== parent.value ) {
+				return;
+			}
+
+			const definingScope = scope.findDefiningScope( node.name );
+
+			if ( ( !definingScope || definingScope.depth === 0 ) && !this.defines[ node.name ] ) {
+				this.dependsOn[ node.name ] = true;
+			}
+		}
+	}
+
+	checkForWrites ( scope, node ) {
+		const addNode = ( node, disallowImportReassignments ) => {
+			while ( node.type === 'MemberExpression' ) {
+				node = node.object;
+			}
+
+			// disallow assignments/updates to imported bindings and namespaces
+			if ( disallowImportReassignments && has( this.module.imports, node.name ) && !scope.contains( node.name ) ) {
+				const err = new Error( `Illegal reassignment to import '${node.name}'` );
+				err.file = this.module.path;
+				err.loc = getLocation( this.module.magicString.toString(), node.start );
+				throw err;
+			}
+
+			if ( node.type !== 'Identifier' ) {
+				return;
+			}
+
+			this.modifies[ node.name ] = true;
+		};
+
+		if ( node.type === 'AssignmentExpression' ) {
+			addNode( node.left, true );
+		}
+
+		else if ( node.type === 'UpdateExpression' ) {
+			addNode( node.argument, true );
+		}
+
+		else if ( node.type === 'CallExpression' ) {
+			node.arguments.forEach( arg => addNode( arg, false ) );
+		}
 	}
 }

src/ast/analyse.js

@@ -4,35 +4,14 @@ import { getName } from '../utils/map-helpers';
 import { has } from '../utils/object';
 import getLocation from '../utils/getLocation';
 
-export default function analyse ( ast, magicString, module ) {
+export default function analyse ( magicString, module ) {
 	let scope = new Scope();
-	let currentTopLevelStatement;
-
-	function addToScope ( declarator ) {
-		var name = declarator.id.name;
-		scope.add( name, false );
-
-		if ( !scope.parent ) {
-			currentTopLevelStatement.defines[ name ] = true;
-		}
-	}
-
-	function addToBlockScope ( declarator ) {
-		var name = declarator.id.name;
-		scope.add( name, true );
-
-		if ( !scope.parent ) {
-			currentTopLevelStatement.defines[ name ] = true;
-		}
-	}
 
 	// first we need to generate comprehensive scope info
 	let previousStatement = null;
 	let commentIndex = 0;
 
 	module.statements.forEach( statement => {
-		currentTopLevelStatement = statement; // so we can attach scoping info
-
 		const node = statement.node;
 
 		let trailing = !!previousStatement;
@@ -54,7 +33,7 @@ export default function analyse ( ast, magicString, module ) {
 			if ( !comment || ( comment.end > node.start ) ) break;
 
 			// attach any trailing comment to the previous statement
-			if ( trailing && !/\n/.test( magicString.slice( previousStatement.node.end, comment.start ) ) ) {
+			if ( trailing && !/\n/.test( module.source.slice( previousStatement.node.end, comment.start ) ) ) {
 				previousStatement.trailingComment = comment;
 			}
 
@@ -77,155 +56,8 @@ export default function analyse ( ast, magicString, module ) {
 		if ( previousStatement ) previousStatement.margin[1] = margin;
 		statement.margin[0] = margin;
 
-		walk( statement.node, {
-			enter ( node ) {
-				let newScope;
-
-				magicString.addSourcemapLocation( node.start );
-
-				switch ( node.type ) {
-					case 'FunctionExpression':
-					case 'FunctionDeclaration':
-					case 'ArrowFunctionExpression':
-						let names = node.params.map( getName );
-
-						if ( node.type === 'FunctionDeclaration' ) {
-							addToScope( node );
-						} else if ( node.type === 'FunctionExpression' && node.id ) {
-							names.push( node.id.name );
-						}
-
-						newScope = new Scope({
-							parent: scope,
-							params: names, // TODO rest params?
-							block: false
-						});
-
-						break;
-
-					case 'BlockStatement':
-						newScope = new Scope({
-							parent: scope,
-							block: true
-						});
-
-						break;
-
-					case 'CatchClause':
-						newScope = new Scope({
-							parent: scope,
-							params: [ node.param.name ],
-							block: true
-						});
-
-						break;
-
-					case 'VariableDeclaration':
-						node.declarations.forEach( node.kind === 'let' ? addToBlockScope : addToScope ); // TODO const?
-						break;
-
-					case 'ClassDeclaration':
-						addToScope( node );
-						break;
-				}
-
-				if ( newScope ) {
-					Object.defineProperty( node, '_scope', { value: newScope });
-					scope = newScope;
-				}
-			},
-			leave ( node ) {
-				if ( node === currentTopLevelStatement ) {
-					currentTopLevelStatement = null;
-				}
-
-				if ( node._scope ) {
-					scope = scope.parent;
-				}
-			}
-		});
+		statement.analyse();
 
 		previousStatement = statement;
 	});
-
-	// then, we need to find which top-level dependencies this statement has,
-	// and which it potentially modifies
-	module.statements.forEach( statement => {
-		function checkForReads ( node, parent ) {
-			if ( node.type === 'Identifier' ) {
-				// disregard the `bar` in `foo.bar` - these appear as Identifier nodes
-				if ( parent.type === 'MemberExpression' && node !== parent.object ) {
-					return;
-				}
-
-				// disregard the `bar` in { bar: foo }
-				if ( parent.type === 'Property' && node !== parent.value ) {
-					return;
-				}
-
-				const definingScope = scope.findDefiningScope( node.name );
-
-				if ( ( !definingScope || definingScope.depth === 0 ) && !statement.defines[ node.name ] ) {
-					statement.dependsOn[ node.name ] = true;
-				}
-			}
-
-		}
-
-		function checkForWrites ( node ) {
-			function addNode ( node, disallowImportReassignments ) {
-				while ( node.type === 'MemberExpression' ) {
-					node = node.object;
-				}
-
-				// disallow assignments/updates to imported bindings and namespaces
-				if ( disallowImportReassignments && has( module.imports, node.name ) && !scope.contains( node.name ) ) {
-					const err = new Error( `Illegal reassignment to import '${node.name}'` );
-					err.file = module.path;
-					err.loc = getLocation( module.code.toString(), node.start );
-					throw err;
-				}
-
-				if ( node.type !== 'Identifier' ) {
-					return;
-				}
-
-				statement.modifies[ node.name ] = true;
-			}
-
-			if ( node.type === 'AssignmentExpression' ) {
-				addNode( node.left, true );
-			}
-
-			else if ( node.type === 'UpdateExpression' ) {
-				addNode( node.argument, true );
-			}
-
-			else if ( node.type === 'CallExpression' ) {
-				node.arguments.forEach( arg => addNode( arg, false ) );
-			}
-
-			// TODO UpdateExpressions, method calls?
-		}
-
-		walk( statement.node, {
-			enter ( node, parent ) {
-				// skip imports
-				if ( /^Import/.test( node.type ) ) return this.skip();
-
-				if ( node._scope ) scope = node._scope;
-
-				checkForReads( node, parent );
-				checkForWrites( node, parent );
-
-				//if ( node.type === 'ReturnStatement')
-
-			},
-			leave ( node ) {
-				if ( node._scope ) scope = scope.parent;
-			}
-		});
-	});
-
-	module.scope = scope;
 }

src/utils/map-helpers.js

@@ -9,3 +9,11 @@ export function quoteId ( x ) {
 export function req ( x ) {
 	return `require('${x.id}')`;
 }
+
+export function isImportDeclaration ( statement ) {
+	return statement.isImportDeclaration;
+}
+
+export function isExportDeclaration ( statement ) {
+	return statement.isExportDeclaration;
+}