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'use strict';
/**
* Copyright (c) 2013-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
*
*/
var aStackPool = [];
var bStackPool = [];
/**
* Checks if two values are equal. Values may be primitives, arrays, or objects.
* Returns true if both arguments have the same keys and values.
*
* @see http://underscorejs.org
* @copyright 2009-2013 Jeremy Ashkenas, DocumentCloud Inc.
* @license MIT
*/
function areEqual(a, b) {
var aStack = aStackPool.length ? aStackPool.pop() : [];
var bStack = bStackPool.length ? bStackPool.pop() : [];
var result = eq(a, b, aStack, bStack);
aStack.length = 0;
bStack.length = 0;
aStackPool.push(aStack);
bStackPool.push(bStack);
return result;
}
function eq(a, b, aStack, bStack) {
if (a === b) {
// Identical objects are equal. `0 === -0`, but they aren't identical.
return a !== 0 || 1 / a == 1 / b;
}
if (a == null || b == null) {
// a or b can be `null` or `undefined`
return false;
}
if (typeof a != 'object' || typeof b != 'object') {
return false;
}
var objToStr = Object.prototype.toString;
var className = objToStr.call(a);
if (className != objToStr.call(b)) {
return false;
}
switch (className) {
case '[object String]':
return a == String(b);
case '[object Number]':
return isNaN(a) || isNaN(b) ? false : a == Number(b);
case '[object Date]':
case '[object Boolean]':
return +a == +b;
case '[object RegExp]':
return a.source == b.source && a.global == b.global && a.multiline == b.multiline && a.ignoreCase == b.ignoreCase;
}
// Assume equality for cyclic structures.
var length = aStack.length;
while (length--) {
if (aStack[length] == a) {
return bStack[length] == b;
}
}
aStack.push(a);
bStack.push(b);
var size = 0;
// Recursively compare objects and arrays.
if (className === '[object Array]') {
size = a.length;
if (size !== b.length) {
return false;
}
// Deep compare the contents, ignoring non-numeric properties.
while (size--) {
if (!eq(a[size], b[size], aStack, bStack)) {
return false;
}
}
} else {
if (a.constructor !== b.constructor) {
return false;
}
if (a.hasOwnProperty('valueOf') && b.hasOwnProperty('valueOf')) {
return a.valueOf() == b.valueOf();
}
var keys = Object.keys(a);
if (keys.length != Object.keys(b).length) {
return false;
}
for (var i = 0; i < keys.length; i++) {
if (!eq(a[keys[i]], b[keys[i]], aStack, bStack)) {
return false;
}
}
}
aStack.pop();
bStack.pop();
return true;
}
module.exports = areEqual;
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