Record Collection Clarification

JavaScript
1

Tell us what’s happening:

I’m hoping to get some clarification on the difference between my solution and the provided solution.

When checking if the ID has a property “tracks” , I decided to use the .hasOwnProperty function to test this. However the provided solution just has the following…

 if(collection[id][prop]) {
    collection[id][prop].push(value);
   }
   else {
    collection[id][prop]=[value];
   }

What is the difference here? Here are my assumtions

  1. An if statement will always be met with a Boolean response, true of false.
  2. Entering the object property path within an if statement will test if it exists?

I also wanted to confirm that the difference between the following statements is that the top one creates values within an array whereas the bottom one just

collection[id][prop]=[value]
 collection[id][prop] = value

I also seem to be getting confused on when to use [ or ( or " or ; within my solutions. Is there a test I can think of within my head to help with this?

Appreciate any help or guidance!

Thanks,

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"
    }
};
// 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) == true) {
    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(5439, "artist", "ABBA");

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

2

Well the simple answer is that:

if(collection[id][prop])

is shorthand for:

if(collection[id][prop] == true) || if(collection[id][prop] != false)

The longer answer is that the section of code collection[id][prop] will be replaced at run time with the value in that variable ( object ) or undefined if it doesn’t exist. So if its not undefined (does not exist) or 0 the statement will be true.