total-sorta

Total Sorta

This is a small set of helper functions, designed to compare array elements. Usually, you'd use them in implementing a sorting algorithm.

I got the idea of wrapping total order into functions from Sedgewick & Wayne's book on Algorithms.

They're reliable, and hopefully the JS community will find them useful too.

Installation

$ npm install total-sorta

Usage

var ts = require('total-sorta');

API

compare(v, w)

Compares two items & returns a result. It's assumed that they have some common characteristic.

Like the <=> (spaceship) operator in Ruby, Perl, PHP or Groovy, it returns:

• -1 if the 1st item is < the 2nd item
• 1 if the 1st item is > the 2nd item
• 0 otherwise

less(v, w)

• Returns true if & only if item v is less than w
• Returns false if the item v is greater than w
• Returns false if the two items are equal

more(v, w)

• Returns true if & only if item v is greater than w
• Returns false if the item v is less than w
• Returns false if the two items are equal

sorted(arr, [option])

Returns true if your array, arr, is sorted. By default, it will check for ascending order. If you want descending order, pass in the option, { descending: true }, as 2nd parameter.

For what it's worth, !condition

This may seem obvious, but it wasn't to me at first. Flip the boolean result with ! to check for 'less than or equal to' or 'greater than or equal to'.

• !more(v, w) is true if v <= w
• !less(v, w) is true if v >= w