Compare alphanumeric strings the same way a human would, using a natural order algorithm (originally known as the alphanum algorithm) where numeric characters are sorted based on their numeric values rather than their ASCII values.
Standard sorting: Natural order sorting:
img1.png img1.png
img10.png img2.png
img12.png img10.png
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This module exports a function that returns a number indicating whether one string should come before, after, or is the same as another string.
It can be used directly with the native .sort() array method.
This module can compare strings containing any size of number and is heavily tested with a custom benchmark suite to make sure that it is as fast as possible.
```sh npm install string-natural-compare --save
yarn add string-natural-compare ```
naturalCompare(strA, strB[, options])strA (string)strB (string)options (object) - Optional options object with the following options:caseInsensitive (boolean) - Set to true to compare strings case-insensitively. Default: false.alphabet (string) - A string of characters that define a custom character ordering. Default: undefined.```js const naturalCompare = require('string-natural-compare');
// Simple, case-sensitive sorting const files = ['z1.doc', 'z10.doc', 'z17.doc', 'z2.doc', 'z23.doc', 'z3.doc']; files.sort(naturalCompare); // -> ['z1.doc', 'z2.doc', 'z3.doc', 'z10.doc', 'z17.doc', 'z23.doc']
// Case-insensitive sorting const chars = ['B', 'C', 'a', 'd']; const naturalCompareCI = (a, b) => naturalCompare(a, b, {caseInsensitive: true}); chars.sort(naturalCompareCI); // -> ['a', 'B', 'C', 'd']
// Note: ['a', 'A'].sort(naturalCompareCI); // -> ['a', 'A'] ['A', 'a'].sort(naturalCompareCI); // -> ['A', 'a']
// Compare strings containing large numbers naturalCompare( '1165874568735487968325787328996865', '265812277985321589735871687040841' ); // -> 1 // (Other inputs with the same ordering as this example may yield a different number > 0)
// Sorting an array of objects const hotelRooms = [ {street: '350 5th Ave', room: 'A-1021'}, {street: '350 5th Ave', room: 'A-21046-b'} ]; // Sort by street (case-insensitive), then by room (case-sensitive) hotelRooms.sort((a, b) => ( naturalCompare(a.street, b.street, {caseInsensitive: true}) || naturalCompare(a.room, b.room) ));
// When text transformation is needed or when doing a case-insensitive sort on a // large array of objects, it is best for performance to pre-compute the // transformed text and store it on the object. This way, the text will not need // to be transformed for every comparison while sorting. const cars = [ {make: 'Audi', model: 'R8'}, {make: 'Porsche', model: '911 Turbo S'} ]; // Sort by make, then by model (both case-insensitive) for (const car of cars) { car.sortKey = (car.make + ' ' + car.model).toLowerCase(); } cars.sort((a, b) => naturalCompare(a.sortKey, b.sortKey));
// Using a custom alphabet (Russian alphabet) const russianOpts = { alphabet: 'АБВГДЕЁЖЗИЙКЛМНОПРСТУФХЦЧШЩЪЫЬЭЮЯабвгдеёжзийклмнопрстуфхцчшщъыьэюя', }; ['Ё', 'А', 'б', 'Б'].sort((a, b) => naturalCompare(a, b, russianOpts)); // -> ['А', 'Б', 'Ё', 'б'] ```
Note: Putting numbers in the custom alphabet can cause undefined behaviour.