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- "use strict";
- var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
- var _assert = _interopRequireDefault(require("assert"));
- var _util = require("./util.js");
- /**
- * Copyright (c) 2014-present, Facebook, Inc.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
- var mMap = new WeakMap();
- function m(node) {
- if (!mMap.has(node)) {
- mMap.set(node, {});
- }
- return mMap.get(node);
- }
- var hasOwn = Object.prototype.hasOwnProperty;
- function makePredicate(propertyName, knownTypes) {
- function onlyChildren(node) {
- var t = (0, _util.getTypes)();
- 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)) {
- _assert["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) {
- (0, _util.getTypes)().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);
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