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deepDiffer.js
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deepDiffer.js
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/**
* Copyright 2013-2015, 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.
*/
'use strict';
// TODO: Move deepDiffer into react
var deepDiffer = function(one: any, two: any): boolean {
if (one === two) {
// Short circuit on identical object references instead of traversing them.
return false;
}
if (typeof one === 'function' && typeof two === 'function') {
// We consider all functions equal
return false;
}
if (typeof one !== 'object' || one === null) {
// Primitives can be directly compared
return one !== two;
}
if (typeof two !== 'object' || two === null) {
// We know they are different because the previous case would have triggered
// otherwise.
return true;
}
if (one.constructor !== two.constructor) {
return true;
}
if (Array.isArray(one)) {
// We know two is also an array because the constructors are equal
var len = one.length;
if (two.length !== len) {
return true;
}
for (var ii = 0; ii < len; ii++) {
if (deepDiffer(one[ii], two[ii])) {
return true;
}
}
} else {
for (var key in one) {
if (deepDiffer(one[key], two[key])) {
return true;
}
}
for (var twoKey in two) {
// The only case we haven't checked yet is keys that are in two but aren't
// in one, which means they are different.
if (one[twoKey] === undefined && two[twoKey] !== undefined) {
return true;
}
}
}
return false;
};
module.exports = deepDiffer;