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node_modules/regenerator-transform/lib/meta.js 3.63 KB
2a09d1a4   liuqimichale   添加宜春 天水 宣化
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  "use strict";
  
  var _assert = require("assert");
  
  var _assert2 = _interopRequireDefault(_assert);
  
  var _babelTypes = require("babel-types");
  
  var t = _interopRequireWildcard(_babelTypes);
  
  function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }
  
  function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
  
  var m = require("private").makeAccessor(); /**
                                              * Copyright (c) 2014, Facebook, Inc.
                                              * All rights reserved.
                                              *
                                              * This source code is licensed under the BSD-style license found in the
                                              * https://raw.github.com/facebook/regenerator/master/LICENSE file. An
                                              * additional grant of patent rights can be found in the PATENTS file in
                                              * the same directory.
                                              */
  
  var hasOwn = Object.prototype.hasOwnProperty;
  
  function makePredicate(propertyName, knownTypes) {
    function onlyChildren(node) {
      t.assertNode(node);
  
      // Assume no side effects until we find out otherwise.
      var result = false;
  
      function check(child) {
        if (result) {
          // Do nothing.
        } else if (Array.isArray(child)) {
          child.some(check);
        } else if (t.isNode(child)) {
          _assert2.default.strictEqual(result, false);
          result = predicate(child);
        }
        return result;
      }
  
      var keys = t.VISITOR_KEYS[node.type];
      if (keys) {
        for (var i = 0; i < keys.length; i++) {
          var key = keys[i];
          var child = node[key];
          check(child);
        }
      }
  
      return result;
    }
  
    function predicate(node) {
      t.assertNode(node);
  
      var meta = m(node);
      if (hasOwn.call(meta, propertyName)) return meta[propertyName];
  
      // Certain types are "opaque," which means they have no side
      // effects or leaps and we don't care about their subexpressions.
      if (hasOwn.call(opaqueTypes, node.type)) return meta[propertyName] = false;
  
      if (hasOwn.call(knownTypes, node.type)) return meta[propertyName] = true;
  
      return meta[propertyName] = onlyChildren(node);
    }
  
    predicate.onlyChildren = onlyChildren;
  
    return predicate;
  }
  
  var opaqueTypes = {
    FunctionExpression: true,
    ArrowFunctionExpression: true
  };
  
  // These types potentially have side effects regardless of what side
  // effects their subexpressions have.
  var sideEffectTypes = {
    CallExpression: true, // Anything could happen!
    ForInStatement: true, // Modifies the key variable.
    UnaryExpression: true, // Think delete.
    BinaryExpression: true, // Might invoke .toString() or .valueOf().
    AssignmentExpression: true, // Side-effecting by definition.
    UpdateExpression: true, // Updates are essentially assignments.
    NewExpression: true // Similar to CallExpression.
  };
  
  // These types are the direct cause of all leaps in control flow.
  var leapTypes = {
    YieldExpression: true,
    BreakStatement: true,
    ContinueStatement: true,
    ReturnStatement: true,
    ThrowStatement: true
  };
  
  // All leap types are also side effect types.
  for (var type in leapTypes) {
    if (hasOwn.call(leapTypes, type)) {
      sideEffectTypes[type] = leapTypes[type];
    }
  }
  
  exports.hasSideEffects = makePredicate("hasSideEffects", sideEffectTypes);
  exports.containsLeap = makePredicate("containsLeap", leapTypes);