43 lines
1.0 KiB
JavaScript
43 lines
1.0 KiB
JavaScript
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/**
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* Returns an array containing the initial elements which both input arrays have in common.
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*
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* A common use-case for this is discovering common ancestors between two file paths.
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*
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* ```js
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* > commonSequence = require("common-sequence");
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*
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* > pathA = "/Users/lloyd/Documents/75lb/dmd".split("/");
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* > pathB = "/Users/lloyd/Documents/75lb/array-tools".split("/");
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*
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* > commonSequence(pathA, pathB).join("/");
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* '/Users/lloyd/Documents/75lb'
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* ```
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*
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* or a more trivial example:
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* ```js
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* > a.commonSequence([ 1, 2, 3 ], [ 1, 2, 4 ])
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* [ 1, 2 ]
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* ```
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* @module common-sequence
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*/
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module.exports = commonSequence
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/**
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* Returns the initial elements which both input arrays have in common
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* @param {Array} - first array to compare
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* @param {Array} - second array to compare
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* @returns {Array}
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* @alias module:common-sequence
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*/
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function commonSequence (a, b) {
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var result = []
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for (var i = 0; i < Math.min(a.length, b.length); i++) {
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if (a[i] === b[i]) {
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result.push(a[i])
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} else {
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break
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}
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}
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return result
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}
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