105 lines
2.9 KiB
JavaScript
105 lines
2.9 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*/
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/*global exports:true*/
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/*jslint node:true*/
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'use strict';
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var Syntax = require('./syntax');
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/**
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* Executes visitor on the object and its children (recursively).
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* While traversing the tree, a scope chain is built and passed to the visitor.
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*
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* If the visitor returns false, the object's children are not traversed.
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*
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* @param {object} object
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* @param {function} visitor
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* @param {?array} scopeChain
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*/
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function traverse(object, visitor, scopeChain) {
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scopeChain = scopeChain || [{}];
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var scope = scopeChain[0];
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switch (object.type) {
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case Syntax.VariableDeclaration:
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object.declarations.forEach(function(decl) {
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scope[decl.id.name] = decl.init;
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});
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break;
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case Syntax.ClassDeclaration:
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scope[object.id.name] = object;
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break;
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case Syntax.FunctionDeclaration:
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// A function declaration creates a symbol in the current scope
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scope[object.id.name] = object;
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/* falls through */
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case Syntax.FunctionExpression:
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case Syntax.Program:
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scopeChain = [{}].concat(scopeChain);
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break;
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}
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if (object.type === Syntax.FunctionExpression ||
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object.type === Syntax.FunctionDeclaration) {
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// add parameters to the new scope
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object.params.forEach(function(param) {
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// since the value of the parameters are unknown during parsing time
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// we set the value to `undefined`.
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scopeChain[0][param.name] = undefined;
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});
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}
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if (object.type) {
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if (visitor.call(null, object, scopeChain) === false) {
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return;
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}
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}
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for (var key in object) {
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if (object.hasOwnProperty(key)) {
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var child = object[key];
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if (typeof child === 'object' && child !== null) {
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traverse(child, visitor, scopeChain);
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}
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}
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}
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}
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/**
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* Executes visitor on the object and its children, but only traverses into
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* children which can be statically analyzed and don't depend on runtime
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* information.
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*
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* @param {object} object
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* @param {function} visitor
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* @param {?array} scopeChain
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*/
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function traverseFlat(object, visitor, scopeChain) {
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traverse(object, function(node, scopeChain) {
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switch (node.type) {
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case Syntax.FunctionDeclaration:
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case Syntax.FunctionExpression:
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case Syntax.IfStatement:
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case Syntax.WithStatement:
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case Syntax.SwitchStatement:
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case Syntax.TryStatement:
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case Syntax.WhileStatement:
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case Syntax.DoWhileStatement:
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case Syntax.ForStatement:
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case Syntax.ForInStatement:
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return false;
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}
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return visitor(node, scopeChain);
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}, scopeChain);
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}
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module.exports = traverseFlat;
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