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ammarkhan
Front End Web Development Techdegree Student 21,661 PointsWhy my code return undefined
I tried it own my own, pretty much the same as answer but it returned 3 undefined. Following is my code
const fruits = ['apple', 'pear', 'cherry'];
const capitalizedFruits = fruits.map(fruit => {
fruit.toUpperCase();
});
The only change I see in Joel code is that he is condensing it to one line. Then why my code won't work?
2 Answers
Michael Hulet
47,913 PointsThis is a little gotcha of JavaScript arrow functions. When you have one statement on one line without any brackets as the entire body of your function like Joel did, JavaScript understands that you mean to return that one statement. Instead, when you expand it into multiple lines like you did, you need to explicitly use the return keyword to have your arrow function return a value. Otherwise, a function that doesn't return anything returns undefined by default, and since your arrow function doesn't return anything, your capitalizedFruits gets filled with undefineds. To fix this, all you need to do is add a return statement to your arrow function, like this:
const capitalizedFruits = fruits.map(fruit => {
return fruit.toUpperCase();
});
Other than this, your code is awesome. Great job!
Jacob TRAN
653 PointsI WAS STUCK ON THIS PROBLEM DUE TO A STUPID KEYWORD 'return'. OooooFFf