// 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;