Write Arrow Functions with Parameters No Function

Why is this giving me a correct answer? The function has no ‘function.’

Your code so far

const myConcat = (arr1, arr2) => 

// test your code
console.log(myConcat([1, 2], [3, 4, 5]));

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36.

Link to the challenge:

In real life this doesn’t work and returns undefined. Maybe there is a bug in the challenge unit test.