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JavaScript

"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);