leave the expression inside 'export default' in the source, evaluate …

…it even if we never access the default export
polyfills · Aug 5, 2014 · d7014e2 · d7014e2
1 parent 124cd57
commit d7014e2
Show file tree

Hide file tree

Showing 2 changed files with 25 additions and 17 deletions.
diff --git a/lib/exports.js b/lib/exports.js
@@ -17,45 +17,46 @@ function isExportDeclaration(node) {
 }
 
 Module.prototype.buildExports = function () {
-  // [expression, exportedVariable]
+  // [localVariable, exportedVariable]
   var exports = []
 
   this.exports.forEach(function (node) {
     var declaration = node.declaration
 
     if (node.default) {
-      exports.push([declaration, 'default'])
+      var id = node._varname = this.sourceToVariableName('default')
+      exports.push([id, 'default'])
       return
     }
 
     if (node.specifiers) {
       return node.specifiers.forEach(function (specifier) {
-        var id = specifier.id
-        exports.push([id, id.name])
+        var id = specifier.id.name
+        exports.push([id, id])
       })
     }
 
     if (n.FunctionDeclaration.check(declaration)) {
-      var id = declaration.id
-      if (!id.name) throw new Error('unnamed function declaration')
-      return exports.push([id, id.name])
+      var id = declaration.id.name
+      if (!id) throw new Error('unnamed function declaration')
+      return exports.push([id, id])
     }
 
     if (n.VariableDeclaration.check(declaration)) {
       return declaration.declarations.forEach(function (declaration) {
-        var id = declaration.id
-        exports.push([id, id.name])
+        var id = declaration.id.name
+        exports.push([id, id])
       })
     }
 
     if (n.ClassDeclaration.check(declaration)) {
-      var id = declaration.id
-      if (!id.name) throw new Error('unnamed class')
-      return exports.push([id, id.name])
+      var id = declaration.id.name
+      if (!id) throw new Error('unnamed class')
+      return exports.push([id, id])
     }
 
     throw new Error('wtf')
-  })
+  }, this)
 
   if (!exports.length) return // nothing to export
 
@@ -71,7 +72,12 @@ Module.prototype.removeExports = function () {
     visitExportDeclaration: function (path) {
       if (path.node.default) {
         // remove `export default`s
-        path.replace()
+        path.replace(b.variableDeclaration('var', [
+          b.variableDeclarator(
+            b.identifier(path.node._varname),
+            path.node.declaration
+          )
+        ]))
       } else if (path.node.specifiers) {
         // remove `export { x, y }`s
         path.replace()
@@ -96,7 +102,7 @@ Module.prototype.removeExports = function () {
  * Returns a property
  */
 
-function buildGetter(expression, as) {
+function buildGetter(name, as) {
   return b.property(
     'init',
     b.identifier(as),
@@ -108,7 +114,7 @@ function buildGetter(expression, as) {
           null,
           [],
           b.blockStatement(
-            [b.returnStatement(expression)]
+            [b.returnStatement(b.identifier(name))]
           )
         )
       ),

diff --git a/test/unit.js b/test/unit.js
@@ -128,10 +128,12 @@ describe('Build Exports', function () {
     var context = vm.createContext()
     vm.runInThisContext(vmExports, context)
     vm.runInThisContext(result.code, context)
-    vm.runInThisContext('if (exports.default() !== "a") throw new Error()', context)
+    // these should be evaluated before we access the default
     vm.runInThisContext('if (a() !== "a") throw new Error()', context)
     vm.runInThisContext('if (o.prop1() !== "a") throw new Error()', context)
     vm.runInThisContext('if (o.prop2() !== "a") throw new Error()', context)
+    // and the default itself
+    vm.runInThisContext('if (exports.default() !== "a") throw new Error()', context)
   })
 
   it('export-multiple', function () {