JavaScript-Developer-I Free Practice Test

A developer needs to test this function:
01const sum3 = (arr) => (
02if (!arr.length) return 0,
03if (arr.length === 1) return arr[0],
04if (arr.length === 2) return arr[0]+ arr[1],
05 return arr[0] + arr[1] + arr[2],
06 );
Which two assert statements are valid tests for the function? Choose 2 answers

1. A. console.assert(sum3(1, ‘2’)) == 12);
2. B. console.assert(sum3(0)) == 0);
3. C. console.assert(sum3(-3, 2 )) == -1);
4. D. console.assert(sum3(‘hello’, 2, 3, 4)) === NaN);

Correct Answer: AC

Refer to the HTML below:

1. A. document.querySelectorAll(‘$main $TONY’)[removed] = ’ M
2. B. ’;
3. C. document.querySelector(‘$main li:second-child’)[removed] = ’ M
4. D. ’;
5. E. document.querySelector(‘$main li.Tony’)[removed] = ’ M
6. F. ’;
7. G. document.querySelector(‘$main li:nth-child(2)’),innerHTML = ’ M
8. H. ’;

Correct Answer: D

Refer to the code below:

Which code executes sayHello once, two minutes from now?

1. A. setTimeout(sayHello, 12000);
2. B. setInterval(sayHello, 12000);
3. C. setTimeout(sayHello(), 12000);
4. D. delay(sayHello, 12000);

Correct Answer: A

Which statement accurately describes the behaviour of the async/ await keyworks ?

1. A. The associated class contains some asynchronous functions.
2. B. The associated function will always return apromise
3. C. The associated function can only be called via asynchronous methods
4. D. The associated sometimes returns a promise.

Correct Answer: B

Refer to the code below:
Let car1 = new Promise((_ , reject) => setTimeout(reject, 2000, “car 1 crashed in” =>
Let car2 =new Promise(resolve => setTimeout(resolve, 1500, “car 2 completed”) Let car3 =new Promise(resolve => setTimeout(resolve, 3000, “car 3 completed”) Promise.race(( car1, car2, car3))
.t hen (value => (
Let result = ‘$(value) the race.’;)}
.catch(arr => {
console.log(“Race is cancelled.”, err);
});
What isthe value of result when Promise.race executes?

1. A. Car 3 completes the race
2. B. Car 2 completed the race.
3. C. Car 1 crashed in the race.
4. D. Race is cancelled.

Correct Answer: B