# Finding errors in code with functions in JavaScript

In the following tasks, some programmer has written code and may have made mistakes in it. You should check if the code does what is described. If the code does not work correctly, you need to fix the errors.

The code should find the sum of the results of two functions work:

`function func1() { console.log(3); } function func2() { console.log(5); } console.log( func1() + func2() );`

The code should find the sum of the array elements:

`function sum(arr) { let res = 0; for (let elem of arr) { res += elem; return res; } } console.log(sum([1, 2, 3, 4, 5]));`

The code should find the sum of the array elements, however, it does not print anything to the console:

`let arr = [1, 2, 3, 4, 5]; function func(arr) { let res = 0; for (let elem of arr) { res += elem; } console.log(res); }`

The code should find the sum of the results of two functions work:

`function func1() { return 3; } function func2() { return 5; } console.log( func1 + func2 );`

The code should find the sum of the array elements:

`let sum = sum([1, 2, 3, 4, 5]); console.log(sum); function sum(arr) { let sum = 0; for (let elem of arr) { sum += elem; } return elem; }`

The code should find the sum of the array elements:

`let res = sum([1, 2, 3, 4, 5]); console.log(res); function sum(arr) { let sum = 0; for (let elem of arr) { sum += elem; } }`

The function append zero to the number from `1` to `9`, and returns the numbers greater than `9` without change:

`function add(num) { if (num <= 9) { return '0' + num; } }`

The code should find the sum of the array elements:

`let arr = [1, 2, 3, 4, 5]; let sum = sum(arr); console.log(sum); function sum(arr) { let res = 0; for (let elem of arr) { res += elem; } return res; }`

The code should find the sum of the digits of a number:

`let num = 12345; let res = getDigitsSum(num); console.log(res); function getDigitsSum(num) { let arr = num.split(''); let sum = 0; for (let elem of arr) { sum += elem; } return sum; }`

The code should check if the number is prime:

`console.log(isPrime(13)); // should output true function isPrime(num) { for (let i = 2; i < num; i++) { if (num % i !== 0) { return true; } else { return false; } } }`
← →
↑
en ru