fix import specifier and export specifier keys

lib/6to5/types/index.js

@@ -355,16 +355,24 @@ t.getIds = function (node, map, ignoreTypes) {
     if (!id) continue;
     if (_.contains(ignoreTypes, id.type)) continue;
 
-    var nodeKey = t.getIds.nodes[id.type];
+    var nodeKeys = t.getIds.nodes[id.type];
     var arrKeys  = t.getIds.arrays[id.type];
 
+    var i, key;
+
     if (t.isIdentifier(id)) {
       ids[id.name] = id;
-    } else if (nodeKey) {
-      if (id[nodeKey]) search.push(id[nodeKey]);
+    } else if (nodeKeys) {
+      for (i in nodeKeys) {
+        key = nodeKeys[i];
+        if (id[key]) {
+          search.push(id[key]);
+          break;
+        }
+      }
     } else if (arrKeys) {
-      for (var i in arrKeys) {
-        var key = arrKeys[i];
+      for (i in arrKeys) {
+        key = arrKeys[i];
         search = search.concat(id[key] || []);
       }
     }
@@ -375,15 +383,15 @@ t.getIds = function (node, map, ignoreTypes) {
 };
 
 t.getIds.nodes = {
-  AssignmentExpression: "left",
-  ImportSpecifier: "name",
-  ExportSpecifier: "name",
-  VariableDeclarator: "id",
-  FunctionDeclaration: "id",
-  ClassDeclaration: "id",
-  MemeberExpression: "object",
-  SpreadElement: "argument",
-  Property: "value"
+  AssignmentExpression: ["left"],
+  ImportSpecifier: ["name", "id"],
+  ExportSpecifier: ["name", "id"],
+  VariableDeclarator: ["id"],
+  FunctionDeclaration: ["id"],
+  ClassDeclaration: ["id"],
+  MemeberExpression: ["object"],
+  SpreadElement: ["argument"],
+  Property: ["value"]
 };
 
 t.getIds.arrays = {