Question

我有这个功能

function isPlayerBanned(name,isbanned){
fs.readFile('bans.json', 'utf8', function (err,data) {
    if (err) {
        console.log(err);
    }

    var retorna;

    var banFile = JSON.parse(data);
    var isBanned = false;
    if ( banFile[name] !== undefined ) {
        isBanned = true;
    }
    if (isBanned){
        var banExpiration = banFile[name];
        var actualTime = new Date();
        var banDate = new Date(banExpiration);
        var timeban = banDate.getTime();
        var time = actualTime.getTime();
        if (time > timeban){
            console.log("oi");
            retorna =  false;
        } else {
            console.log("falhou denovo :(");
            retorna =  true;
        }
    } else {
        console.log('fail 2');
        retorna =  false;
    }
    return isbanned(retorna);
});

}

当我使用时：

isPlayerBanned(WHOIS.account, function(banned){
            if (banned){
                bot.say(channel,from + ": You can't add because you are banned. Use !isbanned [yourauthname] to know when the ban will expire.");
            } else {

节点抛出该错误：“undefined不是函数” 为什么说'isbanned'是未定义的，如果它在函数上？

Answer 1

这样的事情可能是：

function parse(str){
    try { 
        var parsed = JSON.parse(str);
    } catch(e) {
        return false;
    }
    return parsed;
}

// pay attention to the use of "return" to evade indentation! 

// returns 2 arguments in callback 
// 1. error (== null, if no error)
// 2. true (user is banned) or false (user is not banned)
function isPlayerBanned(name, cb){
    fs.readFile('bans.json', 'utf8', function (err,data) {
        if (err) return cb(err);

        var bans = parse(data);
        if (!bans) return cb("JSON.parse failed");

        // if username not in ban list, he is not banned!
        if (!bans[name]) return cb(null, false);            

        // username in ban list, check if ban still active

        var bannedTil = bans[name]; // UNIX timestamp in millisecs
        var now = Date.now(); // UNIX timestamp in millisecs

        // if ban is set to last till a lter point in time
        // than the current time! User is still banned!
        if (bannedTil > now) return cb(null, true);  

        // ban has expired, user not banned anymore
        cb(null, false);

        // TODO: delete the user from the bans.json file
        // if his ban has expired
        // tip: use an event, it's not relevant to the user           
    });
}

isPlayerBanned(WHOIS.account, function(err, banned){
    if (err) return cb(err);

    // banned is true or false, see isPlayerBanned
    if (banned){
        bot.say(channel,from + ": You can't add because you are banned. 
                Use !isbanned [yourauthname] to know when the ban will expire.");
    } else {
        // ...
    }
}

函数中未定义的回调

1 个答案: