Wherefore art thou need Help!

JavaScript
1

Tell us what’s happening:
Here is my code, can someone explain to me why the result is an empty array? I still don’t understand where I made a mistake.

Your code so far


function whatIsInAName(collection, source) {
  var arr = [];
  var convertArr = Object.keys(source); 

  for (let i = 0; i < collection.length; i++) {   
    for (let j = 0; j < convertArr.lengt; j++) {  
       if (collection[i].hasOwnProperty(convertArr[j]) === false || collection[i][convertArr[j]] !== source[convertArr[j]]) { 
         return false;
       }  else {
         arr.push(collection[i]);
       }
    } 
  }

  return arr
}

var result = whatIsInAName([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });
console.log(result)

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) coc_coc_browser/78.0.136 Chrome/72.0.3626.136 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/wherefore-art-thou

2

Well to start, there is no property convertArr.lengt – still working on the logic bit.

Edit: So I went through your code, and there are a few issues. First, the return statement inside the if statement is breaking out of the function entirely. It doesn’t simply break the loop, it exits the function and returns false, completely bypassing the return arr at the end.

I might suggest you change up your logic a little. Here’s some pseudocode to get you thinking. This is solely your nested if statement, the way you’re setting up the array and the keys works fine:

for (iterate over the collection array){
  // Note that this line *has* to be inside the loop, as we want to re-set it each pass.
  create an addToArray variable, set to true.
  for (iterate over they convertArr array of keys) {
    if (the current key DOESN'T exist in the current collection member, OR if the value for that key doesn't match the source value) {
      set the addToArray variable to false
    } // end of the if statement
    // We don't need an else here, as we aren't actually doing the adding here.
  } // end of the loop over the keys
  
  // Here's where any adding to arr happens
  if (addToArray is true){
    add the current member of collection to the arr array
  }
} // end of the iterating over the collection loop

// at this point, we've tested each member, and added the relevant ones.
return arr
1 Like
3

What a silly mistake, thank you very much !!!

4

Easy one to make. Logic issues are a little more challenging, but I hope that pseudocode can help you see the logic.

1 Like
5

Your suggestion really helped me a lot, I passed this test and learned a lot, thank you very much !!!