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MIHA W.LEE
PHP Development Techdegree Graduate 25,452 PointsReduce method
I dont why this doesnt work, I think its close to success. Hope someone can help me out, thank you so much!!
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
numberOf503 = phoneNumbers.reduce((count,number) => {
if(number.charAt(0,5) == '(503)'){
count+1;
}
});
1 Answer
![Steven Parker](https://uploads.teamtreehouse.com/production/profile-photos/969492/micro_tool_chess_set_2.jpg)
Steven Parker
230,688 PointsYou're getting close, but you have a few issues yet:
- "charAt" returns only one character, did you perhaps mean to use "slice"?
- the "+" operator adds without changing the operand, the "+=" operator adds and assigns
- the callback function needs to return the result
- the "reduce" needs an explicit numeric starting value, since the array contains strings
![MIHA W.LEE](https://secure.gravatar.com/avatar/01b9eb74a56c7acc35cd19d607c2b2b3?s=60&d=https%3A%2F%2Fecs-static.teamtreehouse.com%2Fassets%2Fcontent%2Fdefault_avatar-445fbbabfc8dc9188fb5967fe43322ee0c3e0dd1e10f378bf8343784af5a13eb.webp&r=pg)
MIHA W.LEE
PHP Development Techdegree Graduate 25,452 PointsOk, thank you so much! I still confuse about the return keyword, I mean when you should use the return keyword?
![Steven Parker](https://uploads.teamtreehouse.com/production/profile-photos/969492/micro_tool_chess_set_2.jpg)
Steven Parker
230,688 PointsPlace "return count;
" at the end of the callback function (after the "if" block).
MIHA W.LEE
PHP Development Techdegree Graduate 25,452 PointsMIHA W.LEE
PHP Development Techdegree Graduate 25,452 PointsThank you so much!