pretty-sort

sort string with awareness to tailing numeric value

Example

To sort below folder name:

Class 1
Class 2
Class 3
Class 4
Class 10
Class 11
Class 12
Class 13
Group 1
Group 2
Group 3
Group 4
Group 10
Group 11
Group 12

If we sort it by by default string comparison, we will get:

Class 1
Class 10
Class 11
Class 12
Class 13
Class 2
Class 3
Class 4
Group 1
Group 10
Group 11
Group 12
Group 2
Group 3
Group 4

This algorithm will extract the numeric value in the tailing of string, and sort the element by the prefix, then the numeric value.

Hence we will get:

Class 1
Class 2
Class 3
Class 4
Class 10
Class 11
Class 12
Class 13
Group 1
Group 2
Group 3
Group 4
Group 10
Group 11
Group 12

Usage Example

For more examples, see: test/index.ts

import { pretty_sort } from 'pretty-sort'

let list1 = [
  'Group 1',
  'Group 10',
  'Group 2',
  'Group 3'
]

let list2 = pretty_sort(list1)
// list1 === list2
// remark: list1 and list2 reference to the same instance of array
// remark: list1 is updated in-place, similar to Array.sort()

console.log(list2)
/*
[
  'Group 1',
  'Group 2',
  'Group 3',
  'Group 10'
]
*/

Typescript Signature

/** @description main sorting function */
export function pretty_sort(xs: string[]): string[]

/** @description speed up sorting by caching the comparison result, it consumes some memory */
export function enable_tailing_value_memorize(): void

/** @description free up the memory used to cache comparison result */
export function disable_tailing_value_memorize(): void

/** @description helper function */
export function compare(a: any, b: any): 1 | 0 | -1

/**
 * @description helper function
 * @return [numeric value, offset of last non-numeric char]
 * */
export let tailing_value: (s: string) => undefined | [number, number]

/** @description helper function */
export function pretty_compare(a_str: string, b_str: string): 1 | 0 | -1

License

This project is licensed with BSD-2-Clause

This is free, libre, and open-source software. It comes down to four essential freedoms [ref]:

• The freedom to run the program as you wish, for any purpose
• The freedom to study how the program works, and change it so it does your computing as you wish
• The freedom to redistribute copies so you can help others
• The freedom to distribute copies of your modified versions to others