hexo/node_modules/regenerator-transform/lib/meta.js

102 lines
3.0 KiB
JavaScript

"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);