Simple Node.js module to prettify arrays of integers into ranges. This code is based upon a StackOverflow post by Christian C. Salvadó.

Here are a few examples:

• [1,2,3] -> "1-3"
• [1,2,3,5,6,7] -> "1-3, 5-7"
• [1,2,5,6,7] -> "1, 2, 5-7"
• [7,5,6,3,4,10] -> "3-7, 10"

npm install pretty-range

var prettyRange = require("pretty-range");
var input = [7,5,6,3,4,10];
var output = prettyRange(input);
console.log(output);

The outputs is 3-7, 10

If you're using Express and want access to prettyRange() in your views, add the following piece of middleware to your server:

var prettyRange = require("pretty-range");
var express = require("express");
var app = express.createServer();

app.use(prettyRange.middleware);