rejigger path traversal class for es6ification

lib/babel/transformation/transformers/es6/block-scoping-tdz.js

@@ -21,7 +21,7 @@ var visitor = {
 
     if (t.isAssignmentExpression(parent) || t.isUpdateExpression(parent)) {
       if (parent._ignoreBlockScopingTDZ) return;
-      this.parentPath.replaceNode(t.sequenceExpression([assert, parent]));
+      this.parentPath.node = t.sequenceExpression([assert, parent]);
     } else {
       return t.logicalExpression("&&", assert, node);
     }

lib/babel/traversal/path.js

@@ -2,14 +2,12 @@
 
 module.exports = TraversalPath;
 
-/* jshint maxparams:7 */
-
 var traverse = require("./index");
 var includes = require("lodash/collection/includes");
 var Scope    = require("./scope");
 var t        = require("../types");
 
-function TraversalPath(context, parent, obj, key) {
+function TraversalPath(context, parent, container, key) {
   this.shouldRemove = false;
   this.shouldSkip   = false;
   this.shouldStop   = false;
@@ -19,14 +17,30 @@ function TraversalPath(context, parent, obj, key) {
   this.state      = this.context.state;
   this.opts       = this.context.opts;
 
-  this.key     = key;
-  this.obj     = obj;
+  this.container = container;
+  this.key       = key;
 
   this.parent = parent;
-  this.scope  = TraversalPath.getScope(this.getNode(), parent, context.scope);
   this.state  = context.state;
+
+  this.setScope();
 }
 
+TraversalPath.getScope = function (node, parent, scope) {
+  var ourScope = scope;
+
+  // we're entering a new scope so let's construct it!
+  if (t.isScope(node, parent)) {
+    ourScope = new Scope(node, parent, scope);
+  }
+
+  return ourScope;
+};
+
+TraversalPath.prototype.setScope = function () {
+  this.scope = TraversalPath.getScope(this.node, this.parent, this.context.scope);
+};
+
 TraversalPath.prototype.remove = function () {
   this.shouldRemove = true;
   this.shouldSkip   = true;
@@ -45,67 +59,48 @@ TraversalPath.prototype.flatten = function () {
   this.context.flatten();
 };
 
-TraversalPath.getScope = function (node, parent, scope) {
-  var ourScope = scope;
+Object.defineProperty(TraversalPath.prototype, "node", {
+  get: function () {
+    return this.container[this.key];
+  },
 
-  // we're entering a new scope so let's construct it!
-  if (t.isScope(node, parent)) {
-    ourScope = new Scope(node, parent, scope);
-  }
+  set: function (replacement) {
+    var isArray = Array.isArray(replacement);
 
-  return ourScope;
-};
+    // inherit comments from original node to the first replacement node
+    var inheritTo = replacement;
+    if (isArray) inheritTo = replacement[0];
+    if (inheritTo) t.inheritsComments(inheritTo, this.node);
 
-TraversalPath.prototype.maybeRemove = function () {
-  if (this.shouldRemove) {
-    this.setNode(null);
-    this.flatten();
-  }
-};
+    // replace the node
+    this.container[this.key] = replacement;
+    this.setScope();
 
-TraversalPath.prototype.setNode = function (val) {
-  return this.obj[this.key] = val;
-};
-
-TraversalPath.prototype.getNode = function () {
-  return this.obj[this.key];
-};
-
-TraversalPath.prototype.replaceNode = function (replacement) {
-  var isArray = Array.isArray(replacement);
-
-  // inherit comments from original node to the first replacement node
-  var inheritTo = replacement;
-  if (isArray) inheritTo = replacement[0];
-  if (inheritTo) t.inheritsComments(inheritTo, this.getNode());
-
-  // replace the node
-  this.setNode(replacement);
-
-  var file = this.scope && this.scope.file;
-  if (file) {
-    if (isArray) {
-      for (var i = 0; i < replacement.length; i++) {
-        file.checkNode(replacement[i], this.scope);
+    var file = this.scope && this.scope.file;
+    if (file) {
+      if (isArray) {
+        for (var i = 0; i < replacement.length; i++) {
+          file.checkNode(replacement[i], this.scope);
+        }
+      } else {
+        file.checkNode(replacement, this.scope);
       }
-    } else {
-      file.checkNode(replacement, this.scope);
-    }
-  }
-
-  // we're replacing a statement or block node with an array of statements so we better
-  // ensure that it's a block
-  if (isArray) {
-    if (includes(t.STATEMENT_OR_BLOCK_KEYS, this.key) && !t.isBlockStatement(this.obj)) {
-      t.ensureBlock(this.obj, this.key);
     }
 
-    this.flatten();
+    // we're replacing a statement or block node with an array of statements so we better
+    // ensure that it's a block
+    if (isArray) {
+      if (includes(t.STATEMENT_OR_BLOCK_KEYS, this.key) && !t.isBlockStatement(this.container)) {
+        t.ensureBlock(this.container, this.key);
+      }
+
+      this.flatten();
+    }
   }
-};
+});
 
 TraversalPath.prototype.call = function (key) {
-  var node = this.getNode();
+  var node = this.node;
   if (!node) return;
 
   var opts = this.opts;
@@ -115,18 +110,18 @@ TraversalPath.prototype.call = function (key) {
   var replacement = fn.call(this, node, this.parent, this.scope, this.state);
 
   if (replacement) {
-    this.replaceNode(replacement);
-    node = replacement;
+    this.node = replacement;
   }
 
-  this.maybeRemove();
-
-  return node;
+  if (this.shouldRemove) {
+    this.container[this.key] = null;
+    this.flatten();
+  }
 };
 
 TraversalPath.prototype.visit = function () {
   var opts = this.opts;
-  var node = this.getNode();
+  var node = this.node;
 
   // type is blacklisted
   if (opts.blacklist && opts.blacklist.indexOf(node.type) > -1) {
@@ -139,7 +134,7 @@ TraversalPath.prototype.visit = function () {
     return this.shouldStop;
   }
 
-  node = this.getNode();
+  node = this.node;
 
   if (Array.isArray(node)) {
     // traverse over these replacement nodes we purposely don't call exitNode
@@ -154,3 +149,7 @@ TraversalPath.prototype.visit = function () {
 
   return this.shouldStop;
 };
+
+TraversalPath.prototype.isReferencedIdentifier = function () {
+  return t.isReferencedIdentifier(this.node);
+};