getclassmate.js

function getRandom(n, arr, ret) {
    ret = ret || [];
    var randomNum = parseInt(Math.random() * (arr.length - 1), 10);
    if (ret.indexOf(randomNum) === -1) {
        ret.push(randomNum);
    } else {
        getRandom(n, arr, ret);
    }
    return ret.length === n ? ret : getRandom(n, arr, ret);
}

function getClassmate(random, classmates) {
    return random.map(function(item) {
        return classmates[item];
    });
}

function filterClassmate(target, classmates) {
    var less = [];
    for (var i = 0; i < classmates.length; i++) {
        var item = classmates[i];
        if (target.indexOf(item) === -1) {
            less.push(item);
        } else {
            var index = target.indexOf(item);
            target.splice(index, 1);
        }
    }
    return less;
}

var key = 'classmates';
var n = 5;

function getData() {
    return JSON.parse(localStorage.getItem(key)) || ['冷安娜', '朱明萃', '郭华', '唐玉红', '仵恩东', '邱文瑾', '王俊', '王珂', '胡莉莉', '杨荣杰', '徐文枝', '戚文娜', '徐宝龙', '董祥恒', '李玲', '蔡利霞', '孙锐', '唐胜蓝', '朱钰', '王家宇', '郑丽平', '吴美莲', '雷湾', '张梦雪', '祁文', '李奎', '王梦嫦', '武茵倩', '毕石磊', '夏凯', '冷安娜', '朱明萃', '郭华', '唐玉红', '仵恩东', '邱文瑾', '王俊', '王珂', '胡莉莉', '杨荣杰', '徐文枝', '戚文娜', '徐宝龙', '董祥恒', '李玲', '蔡利霞', '孙锐', '唐胜蓝', '朱钰', '王家宇', '郑丽平', '吴美莲', '雷湾', '张梦雪', '祁文', '李奎', '王梦嫦', '武茵倩', '毕石磊', '夏凯'];
}

function saveData(data) {
    localStorage.setItem("classmates", JSON.stringify(data));
}

function main() {
    var classmates = getData();
    if (n > classmates.length) {
        console.log('剩下的人不够抽了');
        return;
    }
    var randomArr = getRandom(n, classmates);
    var targetArr = getClassmate(randomArr, classmates);
    console.log(targetArr.join(',') + '中奖啦');
    var lessClassmate = filterClassmate(targetArr, classmates);
    saveData(lessClassmate);
}

main();