1 files changed, 135 insertions, 0 deletions
diff --git a/remote/test/puppeteer/utils/ESTreeWalker.js b/remote/test/puppeteer/utils/ESTreeWalker.js
new file mode 100644
index 0000000000..1c6c6d4782
--- /dev/null
+++ b/remote/test/puppeteer/utils/ESTreeWalker.js
@@ -0,0 +1,135 @@
+// Copyright (c) 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @unrestricted
+ */
+class ESTreeWalker {
+  /**
+   * @param {function(!ESTree.Node):(!Object|undefined)} beforeVisit
+   * @param {function(!ESTree.Node)=} afterVisit
+   */
+  constructor(beforeVisit, afterVisit) {
+    this._beforeVisit = beforeVisit;
+    this._afterVisit = afterVisit || new Function();
+  }
+
+  /**
+   * @param {!ESTree.Node} ast
+   */
+  walk(ast) {
+    this._innerWalk(ast, null);
+  }
+
+  /**
+   * @param {!ESTree.Node} node
+   * @param {?ESTree.Node} parent
+   */
+  _innerWalk(node, parent) {
+    if (!node) return;
+    node.parent = parent;
+
+    if (this._beforeVisit.call(null, node) === ESTreeWalker.SkipSubtree) {
+      this._afterVisit.call(null, node);
+      return;
+    }
+
+    const walkOrder = ESTreeWalker._walkOrder[node.type];
+    if (!walkOrder) return;
+
+    if (node.type === 'TemplateLiteral') {
+      const templateLiteral = /** @type {!ESTree.TemplateLiteralNode} */ (node);
+      const expressionsLength = templateLiteral.expressions.length;
+      for (let i = 0; i < expressionsLength; ++i) {
+        this._innerWalk(templateLiteral.quasis[i], templateLiteral);
+        this._innerWalk(templateLiteral.expressions[i], templateLiteral);
+      }
+      this._innerWalk(
+        templateLiteral.quasis[expressionsLength],
+        templateLiteral
+      );
+    } else {
+      for (let i = 0; i < walkOrder.length; ++i) {
+        const entity = node[walkOrder[i]];
+        if (Array.isArray(entity)) this._walkArray(entity, node);
+        else this._innerWalk(entity, node);
+      }
+    }
+
+    this._afterVisit.call(null, node);
+  }
+
+  /**
+   * @param {!Array.<!ESTree.Node>} nodeArray
+   * @param {?ESTree.Node} parentNode
+   */
+  _walkArray(nodeArray, parentNode) {
+    for (let i = 0; i < nodeArray.length; ++i)
+      this._innerWalk(nodeArray[i], parentNode);
+  }
+}
+
+/** @typedef {!Object} ESTreeWalker.SkipSubtree */
+ESTreeWalker.SkipSubtree = {};
+
+/** @enum {!Array.<string>} */
+ESTreeWalker._walkOrder = {
+  AwaitExpression: ['argument'],
+  ArrayExpression: ['elements'],
+  ArrowFunctionExpression: ['params', 'body'],
+  AssignmentExpression: ['left', 'right'],
+  AssignmentPattern: ['left', 'right'],
+  BinaryExpression: ['left', 'right'],
+  BlockStatement: ['body'],
+  BreakStatement: ['label'],
+  CallExpression: ['callee', 'arguments'],
+  CatchClause: ['param', 'body'],
+  ClassBody: ['body'],
+  ClassDeclaration: ['id', 'superClass', 'body'],
+  ClassExpression: ['id', 'superClass', 'body'],
+  ConditionalExpression: ['test', 'consequent', 'alternate'],
+  ContinueStatement: ['label'],
+  DebuggerStatement: [],
+  DoWhileStatement: ['body', 'test'],
+  EmptyStatement: [],
+  ExpressionStatement: ['expression'],
+  ForInStatement: ['left', 'right', 'body'],
+  ForOfStatement: ['left', 'right', 'body'],
+  ForStatement: ['init', 'test', 'update', 'body'],
+  FunctionDeclaration: ['id', 'params', 'body'],
+  FunctionExpression: ['id', 'params', 'body'],
+  Identifier: [],
+  IfStatement: ['test', 'consequent', 'alternate'],
+  LabeledStatement: ['label', 'body'],
+  Literal: [],
+  LogicalExpression: ['left', 'right'],
+  MemberExpression: ['object', 'property'],
+  MethodDefinition: ['key', 'value'],
+  NewExpression: ['callee', 'arguments'],
+  ObjectExpression: ['properties'],
+  ObjectPattern: ['properties'],
+  ParenthesizedExpression: ['expression'],
+  Program: ['body'],
+  Property: ['key', 'value'],
+  ReturnStatement: ['argument'],
+  SequenceExpression: ['expressions'],
+  Super: [],
+  SwitchCase: ['test', 'consequent'],
+  SwitchStatement: ['discriminant', 'cases'],
+  TaggedTemplateExpression: ['tag', 'quasi'],
+  TemplateElement: [],
+  TemplateLiteral: ['quasis', 'expressions'],
+  ThisExpression: [],
+  ThrowStatement: ['argument'],
+  TryStatement: ['block', 'handler', 'finalizer'],
+  UnaryExpression: ['argument'],
+  UpdateExpression: ['argument'],
+  VariableDeclaration: ['declarations'],
+  VariableDeclarator: ['id', 'init'],
+  WhileStatement: ['test', 'body'],
+  WithStatement: ['object', 'body'],
+  YieldExpression: ['argument'],
+};
+
+module.exports = ESTreeWalker;