var links = [
{ url: "https://web.archive.org/web/20091001001238/http://www.msn.com/", weight: 1 }, // 5%
{ url: "https://web.archive.org/web/20090331121154/http://www.msn.com/", weight: 2 }, // 10%
{ url: "https://web.archive.org/web/20090831230448/http://www.msn.com/", weight: 3 }, // 15%
{ url: "https://web.archive.org/web/20090301053317/http://www.msn.com/", weight: 4 }, // 20%
{ url: "https://web.archive.org/web/20090731104906/http://www.msn.com/", weight: 10 } // 50%
];
function weightedRandom(arr)
{
var weightSum = arr.map(l => l.weight).reduce((a, b) => a + b, 0);
var rand = Math.random() * weightSum;
var accumulated = 0;
for (var i = 0; i < arr.length; i++)
{
if (rand < accumulated + arr[i].weight)
{
return arr[i];
}
accumulated += arr[i].weight;
}
}
function openSite() {
var link = weightedRandom(links);
// uncomment this and call openSite function:
//var win = window.open(link.url, '_self');
//win.focus();
}
function experiment()
{
var testsCount = 10000;
var counts = {};
for (var i = 0; i < links.length; i++)
{
counts[links[i].url] = 0;
}
for (var i = 0; i < testsCount; i++)
{
var link = weightedRandom(links);
counts[link.url]++;
}
console.log(counts);
}
experiment();