Question

我有这个构造函数：

var Song = function(side, name, index, duration, author, lyrics) {
    this.side = side;
    this.name = name;
    this.index = index;
    this.duration = duration;
    this.author = author;
    this.lyrics = lyrics;
    globalLyrics.push(this.lyrics);
};

然后我创建了24个实例，直到：

var song24 = new Song('Lab', 'Buffalo', 23, '3:10', 'Band', 
    ["this", "tambourine", "is", "waging", "a", "war", "will",
    "drenched", "in", "blood", "flood", "egg", "shape",
    "shaped", "rock", "rocking", "to", "kill", "the", "bull",
    "slay", "slain", "by", "dogs", "snakes", "raven", "scorpio",
    "lion", "headed", "head", "god", "rise"]);

我希望与用户输入相交，例如......

 var input = ["tambourine", "this"];

...与歌词数据库;为此我有一个交叉函数...

function setIntersection(a, b) {

    var result = [];

    for (var i = 0; i < a.length; i++) {
        if (b.indexOf(a[i]) !== -1 && result.indexOf(a[i]) === -1) {
            result.push(a[i]);
        }
    }

    return result;
}

...和prototype function：

Song.prototype.songIntersect = function(input) {

    var bestSong = null;
    var bestCount = -Infinity;

    for (var i = 1; i <= 24; i++) {

        var currentSong = ['song' + i];
        var currentCount = setIntersection(song[i].lyrics, input).length;

        if (currentCount > bestCount) {
            bestSong = currentSong;
            bestCount = currentCount;
        }
    }

    return bestSong.name;
}

但我得到了＃34;歌曲没有定义＆＃34;。错误必须在prototype function中。我在这里想念的是什么？谢谢。

Answer 1

您正在制作24首变量名为T::operator()(T1, T2, T3)，song1等的歌曲。但是，以后当您尝试访问它们时，您正在寻找一个歌曲使用名为song2的不存在的数组。您可以先通过定义一组歌曲来解决这个问题。这也意味着您无需确切知道代码中有多少首歌曲。您可以根据外部源（如数据库，公共API或用户输入）动态添加或删除歌曲。

song

此外，您的var songs = []; // add your songs like this songs.push(new Song(/* ... */));变量是一个数组，其中包含歌曲变量名称的字符串。如果将歌曲存储在数组中，则可以只存储索引或实际歌曲。

currentSong

javascript - 在原型中未定义

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