var rand = function(min, max) {
    return Math.random() * (max - min) + min;
};

var getRandomItem = function(list, weight) {
    var total_weight = weight.reduce(function (prev, cur, i, arr) {
        return prev + cur;
    });

    var random_num = rand(0, total_weight);
    var weight_sum = 0;
    //console.log(random_num)

    for (var i = 0; i < list.length; i++) {
        weight_sum += weight[i];
        weight_sum = +weight_sum.toFixed(2);

        if (random_num <= weight_sum) {
            return list[i];
        }
    }

    // end of function
};

var list = ['javascript', 'php', 'ruby', 'python','lost'];
var weight = [0.15, 0.05, 0.3, 0.5, 0 ];
let arrItem = []
for (var i = 0 ; i < 100;i++) {
  var random_item = getRandomItem(list, weight);
 // console.log(random_item + '');
  arrItem.push(random_item)
}
function searchExist(searchVal ,arr) {
  var count = arr.filter(function(item) {
    return item === searchVal
  }).length;
  console.log('searchVal:' +searchVal +'--:' count)
}

for (var j = 0; k < list.length; j++) {
  searchExist(list[j],arrItem)
}

console.log('1')