Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript JavaScript Array Iteration Methods Array Manipulation Practice map()

Posted by Dwayne Bynum
Dwayne Bynum
10,408 Points

daysOfWeek.map((day)=>{day.substr(0,4)}); Using the curly Braces do not work in any of the challenges WHY?

Although using the arrow function without the curly braces is sometimes more concise the challenges do not accept it as correct syntax.

app.js 
const daysOfWeek = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"];
let abbreviatedDays;

// abbreviatedDays should be: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
// Write your code below

abbreviatedDays = daysOfWeek.map((day)=>{day.slice(0,4)});

1 Answer

Steven Parker
Steven Parker
229,732 Points
Steven Parker
Steven Parker
229,732 Points

First, if you want 3 characters, the 2nd parameter of "slice" should be "3" instead of "4".

Then, either form of the function will work, but you must observe the other differences:

abbreviatedDays = daysOfWeek.map(day => day.slice(0,3));         //compact form has no braces
abbreviatedDays = daysOfWeek.map(day => {return day.slice(0,3);}); //long form needs "return"
Dwayne Bynum
Dwayne Bynum
10,408 Points

Thanks for the Help!