Knowledge check: Advanced JavaScript Features
11. What will print out when the following code runs?
const meal = ["soup", "steak", "ice cream"]
let [starter] = meal;
console.log(starter);
- soup
- ice cream
- steak
13. What will print out when the following code runs?
let food = "Chocolate";
console.log(`My favourite food is ${food}`);
- My favourite food is Chocolate
- My favourite food is ${food}
14. What values will be stored in the set collection after the following code runs?
let set = new Set();
set.add(1);
set.add(2);
set.add(3);
set.add(2);
set.add(1);
- 1, 2, 3, 2, 1
- 1, 2, 3
15. What value will be printed out when the following code runs?
let obj = {
key: 1,
value: 4
};
let output = { ...obj };
output.value -= obj.key;
console.log(output.value);
- 1
- 2
- 3
- 4
16. What value will be printed out when the following code runs?
function count(...basket) {
console.log(basket.length)
}
count(10, 9, 8, 7, 6);
- 10, 9, 8, 7, 6
- 1, 2, 3, 4, 5
- 6
- 5
Knowledge Check - JavaScript in the browser
17. In the following code, the type attribute can be omitted.
< script type="text/javascript">
//Comment
< /script >
- true
- false
18. What does the document variable return in JavaScript?
console.log(document);
- The entire body tag of the webpage in the browser’s memory, as a JavaScript object.
- The entire webpage in the browser’s memory, as a JavaScript object.
- The HTML code of the downloaded webpage, as a JavaScript string.
Shuffle Q/A 2
19. What does the following function return?
getElementById('main-heading')
- It doesn’t return anything.
- All elements that have the class attribute with a value main-heading
- The first element that has the id attribute with a value main-heading
- The last element that has the id attribute with a value main-heading
20. After the following code is run, what will happen when the user clicks on a p element in the browser?
document.querySelector('h1').addEventListener('click',
function() {
console.log('clicked');
});
- ‘clicked’ is printed to the console log.
- Nothing.