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- /**
- * @license Copyright (c) 2003-2016, CKSource - Frederico Knabben. All rights reserved.
- * For licensing, see LICENSE.md.
- */
- /**
- * @module utils/comparearrays
- */
- /**
- * Compares how given arrays relate to each other. One array can be: same as another array, prefix of another array
- * or completely different. If arrays are different, first index at which they differ is returned. Otherwise,
- * a flag specifying the relation is returned. Flags are negative numbers, so whenever a number >= 0 is returned
- * it means that arrays differ.
- *
- * compareArrays( [ 0, 2 ], [ 0, 2 ] ); // 'same'
- * compareArrays( [ 0, 2 ], [ 0, 2, 1 ] ); // 'prefix'
- * compareArrays( [ 0, 2 ], [ 0 ] ); // 'extension'
- * compareArrays( [ 0, 2 ], [ 1, 2 ] ); // 0
- * compareArrays( [ 0, 2 ], [ 0, 1 ] ); // 1
- *
- * @param {Array} a Array that is compared.
- * @param {Array} b Array to compare with.
- * @returns {ArrayRelation} How array `a` is related to `b`.
- */
- export default function compareArrays( a, b ) {
- const minLen = Math.min( a.length, b.length );
- for ( let i = 0; i < minLen; i++ ) {
- if ( a[ i ] != b[ i ] ) {
- // The arrays are different.
- return i;
- }
- }
- // Both arrays were same at all points.
- if ( a.length == b.length ) {
- // If their length is also same, they are the same.
- return 'same';
- } else if ( a.length < b.length ) {
- // Compared array is shorter so it is a prefix of the other array.
- return 'prefix';
- } else {
- // Compared array is longer so it is an extension of the other array.
- return 'extension';
- }
- }
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