Functional Programming - Use Higher-Order Functions map, filter, or reduce to Solve a Complex Problem

[nobumpa]

Tell us what’s happening:
I get TypeError: sqrIntegers.push is not a function. Cannot push() method be used in reduce() method?

Your code so far

const squareList = (arr) => {
  // Only change code below this line
  return arr.reduce((sqrIntegers, num) => {
    return Number.isInteger(num) && num > 0
      ? sqrIntegers.push(num * num)
      : sqrIntegers;
  }, []);  

  
  // Only change code above this line
};

const squaredIntegers = squareList([-3, 4.8, 5, 3, -3.2]);
console.log(squaredIntegers);

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36

Challenge: Functional Programming - Use Higher-Order Functions map, filter, or reduce to Solve a Complex Problem

Link to the challenge:

freeCodeCamp.org

[JeremyLT]

Do you know what the return value of push is?

[nobumpa]

I have looked at some documents and it says push() returns ‘The new lengths property of the object upon which the method was called.’

I also read the explanation ‘concat returns a new array while push returns the length of updated array’ .

Can you please explain how the above difference give different outcome in this problem?

Thanks you for your help.

[JeremyLT]

The callback for reduce needs to return the value that the array is being reduced into. push won’t do that in your ternary.