recordCollection trying to create an array but doesn't work

JavaScript
#1

Tell us what’s happening:
I’ve been trying to create an array inside the object for one hour now, just couldn’t do it.

After updateRecords(recordCollection, 5439, "tracks", "Take a Chance on Me") , tracks should have the string Take a Chance on Me as the last element.

My code just couldn’t pass this step because there isn’t any array at the beginning you have to create one. At the first, I created an empty array but that didn’t work since there are arrays with values. So, I came up with these Array.isArray() idea, but it doesn’t work as I wanted, it creates an array the second time when you pass a value inside the object. Please help.

  **Your code so far**


// Setup
const recordCollection = {
2548: {
  albumTitle: 'Slippery When Wet',
  artist: 'Bon Jovi',
  tracks: ['Let It Rock', 'You Give Love a Bad Name']
},
2468: {
  albumTitle: '1999',
  artist: 'Prince',
  tracks: ['1999', 'Little Red Corvette']
},
1245: {
  artist: 'Robert Palmer',
  tracks: []
},
5439: {
  albumTitle: 'ABBA Gold'
}
};

// Only change code below this line
function updateRecords(records, id, prop, value) {
if(value == ""){
  delete records[id][prop];
} else if(prop == "tracks" && !records[id].hasOwnProperty("tracks")){
  records[id][prop] = value;
} else if(prop == "tracks" && value != undefined){ 
  if(!Array.isArray(records[id][prop])){      
    records[id][prop] = [];          // problem here!!!
  }
  records[id][prop].push(value);
} else {
  records[id][prop] = value;
}

return records;
}

updateRecords(recordCollection, 5439, 'artist', 'ABBA');

  **Your browser information:**

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36

Challenge: Record Collection

Link to the challenge:

#2

No, actually, your issue is here. I suggest you use console.log to see what is being executed and when, and to see the output

2 Likes
#3

I only had to change the order. Thanks again :slight_smile:

  if(value == ""){
    delete records[id][prop];
  } else if(prop == "tracks" && value != undefined){
    if(!Array.isArray(records[id][prop])){
      records[id][prop] = [];
    }
    records[id][prop].push(value);
  } else if(prop == "tracks" && !records[id].hasOwnProperty("tracks")){
    records[id][prop] = value;
  } else {
    records[id][prop] = value;
  }
#4

when is this executed?

#5
  • If prop is tracks but the album doesn’t have a tracks property, create an empty array and add value to it.
#6

isn’t that done with this piece of code?

#7

You seem to have some misunderstandings under the category of “what type of thing is every variable”.

function updateRecords(records, id, prop, value) {
  console.log("records: ", typeof(records));
  console.log("id:      ", typeof(id));
  console.log("prop:    ", typeof(prop));
  console.log("value:   ", typeof(value)); // is this an array?
  console.log("value != undefined:", value != undefined); // will this ever happen?
  return records;
}
#8

yeah you’re right, I deleted the block and it worked anyway

#9 
value != undefined

yes, this was wrong and unnecessary.

my final code

function updateRecords(records, id, prop, value) {
  if(value == ""){
    delete records[id][prop];
  } else if(prop == "tracks"){
    if(!Array.isArray(records[id][prop])){
      records[id][prop] = [];
    }
    records[id][prop].push(value);
  } else {
    records[id][prop] = value;
  }

    return records;
}
1 Like
#10

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