nth
The 'nth' package contains a dirt simple module that takes an integer and then appends the appropriate place suffix. For example:
- 1 becomes 1st
 - 2 becomes 2nd
 - 3 becomes 3rd
 - 4 becomes 4th
 - 13 becomes 13th
 - 23 becomes 23rd
 
Usage
Using the package is very easy. Just download it and install it via NPM:
npm install nth --save 
Once the package is downloaded and installed, you just need to require in the module and call the appendSuffix method:
var nth = require('nth');
var output = nth.appendSuffix(23);
console.log(output); // outputs: '23rd' 
If you just want to get the suffix itself (without the number) then you can call the getSuffix method.
var nth = require('nth');
var output = nth.getSuffix(23);
console.log(output); // outputs: 'rd' 
Contributions
If you find a bug feel free to submit a pull request.
Known Limitations
Beyond the few obvious test cases I haven't spend any time on more complex scenarios like dealing with exponents. I can't imagine many folks really using this library in that context anyway :)