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							113 lines
						
					
					
						
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							113 lines
						
					
					
						
							2.9 KiB
						
					
					
				"use strict"; | 
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 | 
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var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault"); | 
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var _assert = _interopRequireDefault(require("assert")); | 
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var _util = require("./util.js"); | 
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 | 
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/** | 
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 * Copyright (c) 2014-present, Facebook, Inc. | 
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 * | 
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 * This source code is licensed under the MIT license found in the | 
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 * LICENSE file in the root directory of this source tree. | 
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 */ | 
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var mMap = new WeakMap(); | 
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 | 
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function m(node) { | 
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  if (!mMap.has(node)) { | 
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    mMap.set(node, {}); | 
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  } | 
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 | 
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  return mMap.get(node); | 
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} | 
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 | 
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var hasOwn = Object.prototype.hasOwnProperty; | 
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 | 
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function makePredicate(propertyName, knownTypes) { | 
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  function onlyChildren(node) { | 
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    var t = (0, _util.getTypes)(); | 
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    t.assertNode(node); // Assume no side effects until we find out otherwise. | 
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 | 
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    var result = false; | 
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 | 
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    function check(child) { | 
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      if (result) {// Do nothing. | 
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      } else if (Array.isArray(child)) { | 
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        child.some(check); | 
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      } else if (t.isNode(child)) { | 
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        _assert["default"].strictEqual(result, false); | 
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 | 
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        result = predicate(child); | 
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      } | 
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 | 
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      return result; | 
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    } | 
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 | 
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    var keys = t.VISITOR_KEYS[node.type]; | 
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 | 
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    if (keys) { | 
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      for (var i = 0; i < keys.length; i++) { | 
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        var key = keys[i]; | 
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        var child = node[key]; | 
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        check(child); | 
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      } | 
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    } | 
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 | 
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    return result; | 
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  } | 
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 | 
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  function predicate(node) { | 
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    (0, _util.getTypes)().assertNode(node); | 
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    var meta = m(node); | 
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    if (hasOwn.call(meta, propertyName)) return meta[propertyName]; // Certain types are "opaque," which means they have no side | 
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    // effects or leaps and we don't care about their subexpressions. | 
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 | 
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    if (hasOwn.call(opaqueTypes, node.type)) return meta[propertyName] = false; | 
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    if (hasOwn.call(knownTypes, node.type)) return meta[propertyName] = true; | 
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    return meta[propertyName] = onlyChildren(node); | 
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  } | 
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 | 
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  predicate.onlyChildren = onlyChildren; | 
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  return predicate; | 
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} | 
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 | 
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var opaqueTypes = { | 
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  FunctionExpression: true, | 
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  ArrowFunctionExpression: true | 
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}; // These types potentially have side effects regardless of what side | 
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// effects their subexpressions have. | 
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 | 
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var sideEffectTypes = { | 
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  CallExpression: true, | 
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  // Anything could happen! | 
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  ForInStatement: true, | 
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  // Modifies the key variable. | 
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  UnaryExpression: true, | 
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  // Think delete. | 
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  BinaryExpression: true, | 
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  // Might invoke .toString() or .valueOf(). | 
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  AssignmentExpression: true, | 
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  // Side-effecting by definition. | 
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  UpdateExpression: true, | 
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  // Updates are essentially assignments. | 
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  NewExpression: true // Similar to CallExpression. | 
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 | 
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}; // These types are the direct cause of all leaps in control flow. | 
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 | 
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var leapTypes = { | 
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  YieldExpression: true, | 
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  BreakStatement: true, | 
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  ContinueStatement: true, | 
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  ReturnStatement: true, | 
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  ThrowStatement: true | 
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}; // All leap types are also side effect types. | 
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 | 
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for (var type in leapTypes) { | 
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  if (hasOwn.call(leapTypes, type)) { | 
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    sideEffectTypes[type] = leapTypes[type]; | 
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  } | 
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} | 
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 | 
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exports.hasSideEffects = makePredicate("hasSideEffects", sideEffectTypes); | 
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exports.containsLeap = makePredicate("containsLeap", leapTypes); |