Converts a Date object to its relative verbal description.

announceTime.js

var timeIntervals = [
	{start: 0, caption: 'Just now.'},
	{start: 60 * 1000, caption: 'A minute ago.'},
	{start: 2 * 60 * 1000, caption: '@1 minutes ago.'},
	{start: 60 * 60 * 1000, caption: 'An hour ago.'},
	{start: 2 * 60 * 60 * 1000, caption: '@2 hours ago.'},
	{start: 24 * 60 * 60 * 1000, caption: 'Yesterday.'},
	{start: 2 * 24 * 60 * 60 * 1000, caption: '@3 days ago.'},
	{start: 7 * 24 * 60 * 60 * 1000, caption: 'A week ago.'},
	{start: 14 * 24 * 60 * 60 * 1000, caption: '@4 weeks ago.'},
	{start: 30 * 24 * 60 * 60 * 1000, caption: 'A month ago.'},
	{start: 60 * 24 * 60 * 60 * 1000, caption: '@5 months ago.'},
	{start: 365 * 24 * 60 * 60 * 1000, caption: 'A year ago.'},
	{start: 2 * 365 * 24 * 60 * 60 * 1000, caption: '@6 years ago.'},
	{start: 5 * 365 * 24 * 60 * 60 * 1000, caption: 'A long time ago.'}
];

function __sortTimeIntervals(a, b) {
	return a.start == b.start ? 0 : a.start < b.start ? -1 : 1;
}
sort(timeIntervals, __sortTimeIntervals);

function announceTime(t) {
	if (!(t instanceof Date)) return '';
	var now = new Date();
	var diff = now - t;
	
	// Find the right index
	var i = 0;
	while (i < timeIntervals.length - 1 && diff < timeIntervals[i + 1].start) ++i;
	
	replaces = [
		diff / (60 * 1000) | 0,
		diff / (60 * 60 * 1000) | 0,
		diff / (24 * 60 * 60 * 1000) | 0,
		diff / (7 * 24 * 60 * 60 * 1000) | 0,
		diff / (30 * 24 * 60 * 60 * 1000) | 0,
		diff / (365 * 24 * 60 * 60 * 1000) | 0
	];
	
	var result =  timeIntervals[i].caption;
	for (var i = 0; i < replaces.length; ++i) result.replace('@' + i, replaces[i]);
	return result;
}