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hasDataChanged.ts
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hasDataChanged.ts
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/*
* MIT License
*
* Copyright (c) 2016 Microsoft
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
declare var _: any;
/**
* Returns if there is any more or less data in the new data
* @param newData The new set of data
* @param oldData The old set of data
* @param equality Returns true if a and b are referring to the same object, not necessarily if it has changed
*/
export default function hasDataChanged<T>(newData: T[], oldData: T[], equality: (a: T, b: T) => boolean) {
"use strict";
// If the are identical, either same array or undefined, nothing has changed
if (oldData === newData) {
return false;
}
// If only one of them is undefined or if they differ in length, then its changed
if (!oldData || !newData || oldData.length !== newData.length) {
return true;
}
// If there are any elements in newdata that arent in the old data
return _.some(newData, (n: T) => !_.some(oldData, (m: T) => equality(m, n)));
}