https://github.com/gwtw/js-sorting

A collection of sorting algorithms written in JavaScript.
https://github.com/gwtw/js-sorting

Last synced: 10 days ago
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A collection of sorting algorithms written in JavaScript.

• Host: GitHub
• URL: https://github.com/gwtw/js-sorting
• Owner: gwtw
• License: mit
• Created: 2014-06-22T19:16:23.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2016-11-26T15:57:28.000Z (almost 8 years ago)
• Last Synced: 2024-10-03T20:04:05.600Z (about 1 month ago)
• Language: JavaScript
• Size: 162 KB
• Stars: 59
• Watchers: 6
• Forks: 13
• Open Issues: 16
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# js-sorting

[![Build Status](https://travis-ci.org/gwtw/js-sorting.svg?branch=master)](http://travis-ci.org/gwtw/js-sorting)

A collection of sorting algorithms written in JavaScript.

Detailed information on the complexity of each algorithm is located [here][6]. To learn more about how some of the algorithms are implemented, have a look at the [technical articles on my blog][2].

## Installing

```bash

npm install --save js-sorting

```

## Usage

See [the source files][4] for a list sorts available and their public interfaces, Here is an example for [merge sort][5].

```javascript

var mergeSort = require("js-sorting").mergeSort;

// Sort normally

mergeSort([5, 3, 2, 4, 1]);

// Sort in reverse

var reverseCompare = function (a, b) {

    return b - a;

};

mergeSort([5, 3, 2, 4, 1], reverseCompare);

// Sort complex objects

var list = [

  { 'firstname': 'John',   'lastname': 'Smith'   },

  { 'firstname': 'Daniel', 'lastname': 'Imms'    },

  { 'firstname': 'Mary',   'lastname': 'Jackson' },

  { 'firstname': 'John',   'lastname': 'Brown'   },

  { 'firstname': 'Mary',   'lastname': 'Harris'  },

];

var complexNameSort = function (a, b) {

  // Sort by first name first

  if (a.firstname.toLowerCase() < b.firstname.toLowerCase()) return -1;

  if (a.firstname.toLowerCase() > b.firstname.toLowerCase()) return 1;

  // Sort by last name second

  if (a.lastname.toLowerCase() < b.lastname.toLowerCase()) return -1;

  if (a.lastname.toLowerCase() > b.lastname.toLowerCase()) return 1;

  return 0;

};

mergeSort.sort(list, complexNameSort);

```

### Observing array changes

In order to support [one of my other projects][8], various methods are exposed for each sort that allow observation of internal array changes. This can be done by wrapping the functions like so:

```javascript

bubbleSort.attachCompareObserver = function (array, a, b) {

  alert('Comparing "' + array[a] + '" (i=' + a + ') with "' +

                        array[b] + '" (i=' + b + ')');

};

bubbleSort.attachSwapObserver(function (array, a, b) {

  alert('Swapping "' + array[a] + '" (i=' + a + ') with "' +

                       array[b] + '" (i=' + b + ')');

});

```

The functions available are different for each algorithm since not all sorts only do compares and swaps to transform the array in a standard way. For example [insertion sort exposes a `shift` function][9] which shifts an item to a particular index. While this is the same as swapping the item with the adjacent item until it reaches the index, it is achieved in half the number of assignments by only assigning the item being shifted once. The way that this operation is visualised is quite different to just x swaps.

## Contributing

I'd love to get some contributions for other sorting algorithms, if you want to make a pull request try to follow the existing style of the code and make sure you add tests for the new algorithm.

### Testing locally

```bash

npm install

npm test

# generate coverage report in ./coverage/

grunt coverage

```

## License

MIT © [Daniel Imms](http://www.growingwiththeweb.com)

## See also

* [js-data-structures](https://github.com/gwtw/js-data-structures)

* [js-design-patterns](https://github.com/gwtw/js-design-patterns)

* [js-interview-questions](https://github.com/gwtw/js-interview-questions)

[1]: https://github.com/umdjs/umd/blob/master/returnExportsGlobal.js

[2]: http://www.growingwiththeweb.com/p/explore.html?t=Sorting

[4]: lib

[5]: lib/merge-sort.js

[6]: lib/README.md

[8]: https://github.com/gwtw/sorting-visualiser

[9]: lib/insertion-sort.js