Checkpoint: Record Collection

Instructions

You are given a JSON object representing (a small part of) your record collection. Each album is identified by a unique id number and has several properties. Not all albums have complete information.

Write a function which takes an id, a property (prop), and a value.

For the given id in collection:

If value is non-blank (value !== ""), then update or set the value for the prop.

If the prop is "tracks" and value is non-blank, push the value onto the end of the tracks array.

If value is blank, delete that prop.

Always return the entire collection object.

Remember to use Read-Search-Ask if you get stuck. Try to pair program. Write your own code.

Useful Links

• Challenge: Accessing Objects Properties with Bracket Notation
• Challenge: Add New Properties to a JavaScript Object
• Challenge: Delete Properties from a JavaScript Object
• Challenge: Accessing Nested Objects in JSON

Problem Explanation:

• Change the code below // Only change code below this line and up to // Alter values below to test your code
• Take note that you are editing the inside of the update function
• For the given id parameter, which is associated to the collection object:
  • If the value parameter isn't an empty string, update (or set) the value parameter for the prop parameter
  • If the prop parameter is equal to "tracks" and the value isn't an empty string, push the value onto the end of the tracks array
  • If value is an empty string, delete that prop from the object
• Finally, return the collection object

Hint: 1

• Use an else if statement to check the needed steps.

Hint: 2

• The second step listed in the instructions should be first in your else if statement.

Hint: 3

• To access the value of a key in this object, you will use collection[id][prop]

Spoiler Alert!

Solution ahead!

Code Solution:

function update(id, prop, value) {
  if (prop === "tracks" && value !== "") {
    collection[id][prop].push(value);
  } else if (value !== ""){
    collection[id][prop] = value;
  } else {
    delete collection[id][prop];
  }

  return collection;
}

Code Explanation:

• First checks if prop is equal to tracks AND if value isn't a blank string. If both tests pass, value is pushed into the tracks array.
• If that first check doesn't pass, it next checks only if value isn't a blank string. If that test passes, either a new key (prop) and value (value) are added to the object, or an existing key is updated if the prop already exists.
• If both these checks fail (meaning value must be an empty string), then the key (prop) is removed from the object.

Example Run

• update(5439, "artist", "ABBA"); runs
• prop is equal to "artist", not "tracks", so the first part of the else if statement fails
• value is not a blank string, so the second part of the else if statement passes
• artist: "ABBA" is added to the 5439 id

Credits:

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