我被这个挑战难住了,我真的不明白为什么我的代码不能工作。挑战是来自Freecodecamp的"Basic JavaScript: Record Collection“。
挑战是:
“如果value参数不是空字符串,则更新(或设置) prop参数的value参数。如果prop参数等于tracks并且该值不是空字符串,则将该值推入tracks数组的末尾。如果value为空字符串,则从对象中删除该prop。最后,返回集合对象。
代码:
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"
}
};
// Keep a copy of the collection for tests
var collectionCopy = JSON.parse(JSON.stringify(collection));
// Only change code below this line
function updateRecords(id, prop, value) {
if (prop === "tracks" && value !== "") {
if (collection.id.hasOwnProperty(prop)) {
collection[id][prop].push(value);
}
else {
collection.id.prop = [value];
}
}
else if (value !== "") {
collection.id.prop = value;
}
else {
delete collection.id.prop;
}
return collection;
}
// Alter values below to test your code
updateRecords(2468, "tracks", "ABBA");
https://stackoverflow.com/questions/51794932
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