range.js – JavaScript's missing range function

Features:

• The browser and node are both supported.
• Simple: Always returns an array.
• Numeric and decimal ranges.
• Letter ranges.
• Plain syntax range('a', 'z') and Ruby-style range('a..z').
• Reversed ranges.
• Ranges with steps.

Usage

• Node: $ npm install range.js

  var range = require('range.js');

• Browser: Grab lib/strukt.js and include it in your HTML document.

  If an AMD or CommonJS loader is present it will be used, otherwise range is assigned to window.range.

Syntax

There are two different syntaxes, the plain one and the Ruby style one.

// Plain syntax:
range(from, to, step);

// Ruby style syntax:
range('from..to', step);

For convience, the rest of this documentation will use the plain syntax.

Numeric ranges

range(1, 5); // [1, 2, 3, 4, 5]
range(-2, 2); // [-2, -1, 0, 1, 2]
range(0, 0.5, 0.1); // Approximately, JS floats are not exact: [0.1, 0.2, 0.3, 0.4, 0.5]

Letter ranges

range('a', 'd'); // ['a', 'b', 'c', 'd']
range('A', 'D'); // ['A', 'B', 'C', 'D']
range('y', 'B'); // ['y', 'z', 'A', 'B']
range('Y', 'b'); // ['Y', 'Z', 'a', 'b']

Ranges with steps

range(0, 9, 3); // [0, 3, 6, 9]
range('a', 'e', 2); // ['a', 'c', 'e']

Reversed ranges

range(5, 0); // [5, 4, 3, 2, 1, 0]
range('e', 'a'); ['e', 'd', 'c', 'b', 'a']

Ruby style syntax

range('1..5'); // range(1, 5)
range('a..z'); // range('a', 'z')

// Steps:
range('1..5', 2); // range(1, 5, 2)

// Exclusive ranges:
range('1...5'); // [1, 2, 3, 4]

Test suite

The test suite uses the mocha testing framework and the chai assertion library.

Running the tests from the command line:

$ git clone git://github.com/js-coder/struct.js.git && cd struct.js
$ npm install
$ grunt test

Clone this repository, then visit ./spec/index.html in your browser.