Calculate years since a date (eg. a person's age given date of birth)
npm install s-age !Dependencies  
s-age is a function that calculates years since a date. Input can be a date string, timestamp, or Date object.``javascript
var age = require('s-age');
age('2012'); // returns 6 (in 2018)
age('Dec 2 2012'); // returns 5 (in January 2018)
age(new Date()); // returns 0
age(1356728100000); // returns 5 (in 2018)
``