ES6 arrow function returns undefined instead of desired value

问题

Easy function that works in JS without ES6:

var evenOrOdd = function(n){
   if(n % 2 == 1){
      return "Odd";
   } else {
      return "Even";
   }
}

console.log(evenOrOdd(3)); //returns odd

My attempt at restructuring this using ES6:

const evenOrOdd = (n) => {(n % 2 == 1) ? "Odd" : "Even"};

console.log(evenOrOdd(3)); //returns undefined

I'm following these examples here: 2ality and stoimen.

Why is this arrow function returning undefined?

回答1:

You have to remove the {}.

const evenOrOdd = n => (n % 2 === 1 ? "odd" : "even")

console.log(evenOrOdd(3)) //=> "odd"

来源：https://stackoverflow.com/questions/44852417/es6-arrow-function-returns-undefined-instead-of-desired-value