Tell us what’s happening:
The video provided was very helpful for this challenge, however I have a question about the solution. I want to be sure I am fully understanding this before I move on to the next challenge.
in the code:
else if (prop === “tracks”) {
collection[id][prop] = collection[id][prop] || ;
collection[id][prop].push(value);
}
I understand that this checks for a tracks prop, then creates one if there isn’t one and pushes the added value to the end of the array. My question involves the line “collection[id][prop] = collection[id][prop]”. I don’t fully understand how this makes track: appear if it wasn’t already there. I understand how “tracks” gets there, but how does the colon appear? I passed this challenge but not entirely confident of how I did so. I’m really just trying to understand how the collection[id][prop] = collection[id][prop] functions and what its full purpose is in the code.
SPOILER ALERT!!!
Your code so far
// Setup
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"
}
};
// Only change code below this line
function updateRecords(id, prop, value) {
if (value === "") {
delete collection[id][prop];
} else if (prop === "tracks") {
collection[id][prop] = collection[id][prop] || [];
collection[id][prop].push(value);
} else {
collection[id][prop] = value;
}
return collection;
}
updateRecords(2468, "tracks", "hs");
console.log(collection)
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Challenge: Record Collection
Link to the challenge: