输出:
错误代码如下:
// 初始化变量
var collection = {
2548: {
album: "Slippery When Wet",
artist: "Bon Jovi",
tracks: [
"Let It Rock",
"You Give Love a Bad Name"
]
},
2468: {
album: "1999",
artist: "Prince",
tracks: [
"1999",
"Little Red Corvette"
]
},
1245: {
artist: "Robert Palmer",
tracks: [ ]
},
5439: {
album: "ABBA Gold"
}
};
// 深拷贝 collection,用于测试
var collectionCopy = JSON.parse(JSON.stringify(collection));
// 请只修改这条注释以下的代码
function update(id, prop, value) {
var artist = "";
if(value != '' && value != collection[id][prop]){
collection[id][prop] = value;
} else if(value != '' && prop == "tracks"){
collection[id][prop].push(value);
} else if(value == "") {
delete collection[id][prop];
}
return collection;
}
// 你可以修改这一行来测试你的代码
update(5439, "artist", "ABBA");
update(1245, "tracks", "Addicted to Love");
如果不注意if的顺序,可能符合第二个else if的情况会执行if 语句,导致没法执行else if 语句,将两者的顺序交互,就对了
使用if…else if…的时候,一定要注意条件的唯一性。