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JavaScript JavaScript Array Iteration Methods Array Manipulation Practice reduce()

numberOf503 not storing correct value

Hello All,

My code doesn't seem to be working and the error message is that numberOf503 is not storing the correct value.

app.js
const phoneNumbers = ["(503) 123-4567", "(646) 123-4567", "(503) 987-6543", "(503) 234-5678", "(212) 123-4567", "(416) 123-4567"];
let numberOf503;

// numberOf503 should be: 3
// Write your code below
const callBack = (total, phoneNum) => {
  if(phoneNum.search('(503)') !== -1) { return (total + 1); }
}

numberOf503 = phoneNumbers.reduce(callBack, 0);

2 Answers

Simon Coates
Simon Coates
4,965 Points

It seems to accept:

const phoneNumbers = ["(503) 123-4567", "(646) 123-4567", "(503) 987-6543", "(503) 234-5678", "(212) 123-4567", "(416) 123-4567"];
let numberOf503;

// numberOf503 should be: 3
function getTally(total, num) {
  if(num.startsWith("(503)")) return total + 1;
  else return total;
}

numberOf503 = phoneNumbers.reduce(getTally, 0);

Hello Simon,

Yes, this is exactly what I figured the problem to be ( a missing else statement ) as noted in my message below. I didn't realize you had posted an answer until AFTER I posted my comment below. Nonetheless, I have voted your answer as the best answer.

Nvm, I think I figured it out. I need another return statement outside of the if statement, otherwise for cases that don't match the if condition the accumulator gets undefined.