Basic JavaScript: dot & bracket notation question re: Record Collection

Tell us what’s happening:

In the how-to video, the instructor says that we have to use bracket notation in our function. Why can’t we use dot notation?

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 (prop !== tracks && value !== ""){
  collection[id][prop] = value;
} else if(prop === "tracks"){
  collection[id][prop] = collection[id][prop] || [];
  collection[id][prop] = value;
}

return collection;
}

// Alter values below to test your code
updateRecords(5439, "artist", "ABBA");

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Challenge: Record Collection

Link to the challenge:
https://www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/basic-javascript/record-collection