Everything Be True: What Did I Miss?

JavaScript
1

So I made it through this challenge, with the help of the hints (OK…and also the spoilers!). What I’m not sure about, though, is why my original solution was returning “false” for all possible inputs. Here is the code:


function truthCheck(collection, pre) {
  

    for (let i = 0; i < collection.length; i++) {
      if (collection[i].hasOwnProperty(pre) === false) { 
        return false;
       }
      else if (Boolean(collection[i].pre) === false) {
        return false;
      }
    }
    return true;
  }

What I thought this for-loop would do:
1: Iterate through every object in the array
2: Test if the object had the pre property; label the collection “false” if not
3: If the object did have pre, then test to see if its value was truthy; label the whole collection “false” if not
4: Finally, if the entire loop is completed without 2 or 3 finding anything, return true.

Why didn’t I ever get to scenario 4 in this code? I understand why the solutions to this challenge work, but I also want to know why this solution didn’t work. Thanks!

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Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/everything-be-true/

2

One error I can see is

You are using dot notation here, which means it will explicitly search for a property with the word “pre”. You need to use bracket notation to make it dynamic.

2 Likes
3

Thank you! I changed it to bracket notation and it worked perfectly. Glad to see that I had the basic gist of it!