Basic JavaScript: Record Collection

JavaScript
#1

why is this code not the right answer??

function updateRecords(id, prop, value) {

function updateRecords(id, prop, value) {

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

  return collection;
}
#2

Can you attach a link to the challenge ?

#3

First, I will assume you did not mean to post two of the same line (below)

function updateRecords(id, prop, value) {

If my assumption is correct, then you are actually wondering why the following code does not work. I took the liberty of properly indenting your code to make it more readable.


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

Your first if statement ask if value evaluates to true. As long as value is not a falsy value (0, “”, NaN, undefined, null), then this if statement will always evaluate to true which will cause the 2nd (nested) if statement to ask if collection[i][prop] evaluates to true. Again as long as the value of collection[id][prop] is not a falsy value, then it will execute the following line, which attempts to push value into collection[id][prop]. The push method will only work on arrays. So, if collection[id][prop] is not an array, then your code will error out.

collection[id][prop].push(value);

Let’s examine one of the test cases which your solution faiils.

After updateRecords(5439, “tracks”, “Take a Chance on Me”), tracks should have “Take a Chance on Me” as the last element.

In this test case value = “Take a Chance on Me”, so your first if statement evaluates to true, so then we evaluates the 2nd if statement. Since collection[id][prop] is undefined, because prop is “tracks” and there is no “tracks” property for id of 5439, your else block of code (shown below) executes and assigns the “tracks” property the string “Take a Chance on Me”.

Because the tracks property should contain an array of one element ( the string “Take a Change on Me”), you fail the test case.

1 Like
#4

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

#5