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Hamzah Iqbal
Full Stack JavaScript Techdegree Student 11,145 PointsThis reduce method should work, but why isn't it?
```const phoneNumbers = ["(503) 123-4567", "(646) 123-4567", "(503) 987-6543", "(503) 234-5678", "(212) 123-4567", "(416) 123-4567"]; let numberOf503;
numberOf503 = phoneNumbers.reduce((sum, phoneNumber) => {
if(phoneNumber.substring(2,4) === "503") {
return phoneNumbers +1;
} return phoneNumbers;
},0); // numberOf503 should be: 3 // Write your code below
console.log(numberOf503);
Right now it is returning the last in the array, but I can't see why. The substring should return the specified digits.
```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 = phoneNumbers.reduce((sum, phoneNumber) => {
if(phoneNumber.substring(2,4) === "503") {
return phoneNumbers +1;
}
return phoneNumbers;
},0);
// numberOf503 should be: 3
// Write your code below
console.log(numberOf503);
1 Answer
Steven Parker
231,184 PointsIt looks like there are two issues:
- string indexes begin at zero, and the substring stop value should be the value after the last index
- the function should return the total (sum) instead of the array itself (phoneNumbers)
numberOf503 = phoneNumbers.reduce((sum, phoneNumber) => {
if (phoneNumber.substring(1,4) === "503") {
return sum + 1;
}
return sum;
}, 0);