add support for export extensions https://github.com/leebyron/ecmascript-more-export-from - closes #1091

src/acorn/src/statement.js

@@ -559,10 +559,10 @@ pp.parseExport = function(node) {
   this.next()
   // export * from '...'
   if (this.eat(tt.star)) {
-    this.expectContextual("from")
-    node.source = this.type === tt.string ? this.parseExprAtom() : this.unexpected()
-    this.semicolon()
-    this.checkExport(node)
+    if (this.options.features["es7.exportExtensions"] && this.eatContextual("as")) {
+      node.exported = this.parseIdent()
+    }
+    this.parseExportFrom(node)
     return this.finishNode(node, "ExportAllDeclaration")
   }
   if (this.eat(tt._default)) { // export default ...
@@ -587,6 +587,10 @@ pp.parseExport = function(node) {
     node.declaration = this.parseStatement(true)
     node.specifiers = []
     node.source = null
+  } else if (this.type === tt.name) {
+    node.exported = this.parseIdent()
+    this.parseExportFrom(node)
+    return this.finishNode(node, "ExportNamespaceDeclaration")
   } else { // export { x, y as z } [from '...']
     node.declaration = null
     node.specifiers = this.parseExportSpecifiers()
@@ -601,6 +605,13 @@ pp.parseExport = function(node) {
   return this.finishNode(node, "ExportNamedDeclaration")
 }
 
+pp.parseExportFrom = function(node) {
+  this.expectContextual("from")
+  node.source = this.type === tt.string ? this.parseExprAtom() : this.unexpected()
+  this.semicolon()
+  this.checkExport(node)
+}
+
 pp.shouldParseExportDeclaration = function() {
   return this.options.features["es7.asyncFunctions"] && this.isContextual("async")
 }

src/babel/generation/generators/modules.js

@@ -21,8 +21,21 @@ export function ExportSpecifier(node, print) {
   }
 }
 
+export function ExportNamespaceDeclaration(node, print) {
+  this.push("export ");
+  print(node.exported);
+  this.push(" from ");
+  print(node.source);
+  this.semicolon();
+}
+
 export function ExportAllDeclaration(node, print) {
-  this.push("export * from ");
+  this.push("export *");
+  if (node.exported) {
+    this.push(" as ");
+    print(node.exported);
+  }
+  this.push(" from ");
   print(node.source);
   this.semicolon();
 }

src/babel/transformation/modules/_default.js

@@ -62,7 +62,7 @@ var exportsVisitor = traverse.explode({
         extend(formatter.localExports, declar.getBindingIdentifiers());
       }
 
-      if (!t.isExportDefaultDeclaration(node)) {
+      if (!t.isExportDefaultDeclaration(node) && !t.isExportNamespaceDeclaration(node)) {
         formatter.hasNonDefaultExports = true;
       }
 

src/babel/transformation/transformers/es7/export-extensions.js

@@ -0,0 +1,25 @@
+// https://github.com/leebyron/ecmascript-more-export-from
+
+import * as t from "../../../types";
+
+export function check(node) {
+  return t.isExportNamespaceDeclaration(node) || (t.isExportAllDeclaration(node) && node.exported);
+}
+
+export function ExportNamespaceDeclaration(node, parent, scope) {
+  var uid = scope.generateUidIdentifier("default");
+  return [
+    t.importDeclaration([t.importDefaultSpecifier(uid)], node.source),
+    t.exportDefaultDeclaration(uid)
+  ];
+}
+
+export function ExportAllDeclaration(node, parent, scope) {
+  if (node.exported) {
+    var uid = scope.generateUidIdentifier(node.exported.name);
+    return [
+      t.importDeclaration([t.importNamespaceSpecifier(uid)], node.source),
+      t.exportNamedDeclaration(null, [t.exportSpecifier(uid, node.exported)])
+    ];
+  }
+}

src/babel/transformation/transformers/index.js

@@ -84,6 +84,7 @@ export default {
   runtime:                                require("./other/runtime"),
 
   // needs to be before `_blockHoist` due to function hoisting etc
+  "es7.exportExtensions":                  require("./es7/export-extensions"),
   "es6.modules":                           require("./es6/modules"),
 
   _blockHoist:                             require("./internal/block-hoist"),

src/babel/types/alias-keys.json

@@ -14,10 +14,12 @@
   "EmptyStatement":           ["Statement"],
   "LabeledStatement":         ["Statement"],
   "VariableDeclaration":      ["Statement", "Declaration"],
-  "ExportAllDeclaration":     ["Statement", "Declaration", "ModuleDeclaration", "ExportDeclaration"],
-  "ExportDefaultDeclaration": ["Statement", "Declaration", "ModuleDeclaration", "ExportDeclaration"],
-  "ExportNamedDeclaration":   ["Statement", "Declaration", "ModuleDeclaration", "ExportDeclaration"],
-  "ImportDeclaration":        ["Statement", "Declaration", "ModuleDeclaration"],
+
+  "ExportNamespaceDeclaration": ["Statement", "Declaration", "ModuleDeclaration", "ExportDeclaration"],
+  "ExportAllDeclaration":       ["Statement", "Declaration", "ModuleDeclaration", "ExportDeclaration"],
+  "ExportDefaultDeclaration":   ["Statement", "Declaration", "ModuleDeclaration", "ExportDeclaration"],
+  "ExportNamedDeclaration":     ["Statement", "Declaration", "ModuleDeclaration", "ExportDeclaration"],
+  "ImportDeclaration":          ["Statement", "Declaration", "ModuleDeclaration"],
 
   "ArrowFunctionExpression": ["Scopable", "Function", "Expression"],
   "FunctionDeclaration":     ["Scopable", "Function", "Statement", "Declaration"],

src/babel/types/visitor-keys.json

@@ -22,10 +22,6 @@
   "DoWhileStatement":          ["body", "test"],
   "DoExpression":              ["body"],
   "EmptyStatement":            [],
-  "ExportAllDeclaration":      ["source"],
-  "ExportDefaultDeclaration":  ["declaration"],
-  "ExportNamedDeclaration":    ["declaration", "specifiers", "source"],
-  "ExportSpecifier":           ["local", "exported"],
   "ExpressionStatement":       ["expression"],
   "File":                      ["program"],
   "ForInStatement":            ["left", "right", "body"],
@@ -72,6 +68,12 @@
   "WithStatement":             ["object", "body"],
   "YieldExpression":           ["argument"],
 
+  "ExportAllDeclaration":       ["source", "exported"],
+  "ExportNamespaceDeclaration": ["exported"],
+  "ExportDefaultDeclaration":   ["declaration"],
+  "ExportNamedDeclaration":     ["declaration", "specifiers", "source"],
+  "ExportSpecifier":            ["local", "exported"],
+
   "AnyTypeAnnotation":           [],
   "ArrayTypeAnnotation":         ["elementType"],
   "BooleanTypeAnnotation":       [],