48. What's the output?
console.log(3 + 4 + '5');
console.log(3 + 4 + '5');
Anonymous Quiz
0%
A: "345"
100%
B: "75"
0%
C: 12
0%
D: "12"
49. What's the value of num?
const num = parseInt('7*6', 10);
const num = parseInt('7*6', 10);
Anonymous Quiz
0%
A: 42
0%
B: "42"
100%
C: 7
0%
D: NaN
50. What's the output?
[1, 2, 3].map(num => {
if (typeof num === 'number') return;
return num * 2;
});50. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
0%
A: []
0%
B: [null, null, null]
100%
C: [undefined, undefined, undefined]
0%
D: [ 3 x empty ]
51. What's the output?
function getInfo(member, year) {
member.name = 'Lydia';
year = '1998';
}
const person = { name: 'Sarah' };
const birthYear = '1997';
getInfo(person, birthYear);
console.log(person, birthYear);51. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
100%
A: { name: "Lydia" }, "1997"
0%
B: { name: "Sarah" }, "1998"
0%
C: { name: "Lydia" }, "1998"
0%
D: { name: "Sarah" }, "1997"
52. What's the output?
function greeting() {
throw 'Hello world!';
}
function sayHi() {
try {
const data = greeting();
console.log('It worked!', data);
} catch (e) {
console.log('Oh no an error:', e);
}
}
sayHi();52. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
0%
A: It worked! Hello world!
0%
B: Oh no an error: undefined
0%
C: SyntaxError: can only throw Error objects
100%
D: Oh no an error: Hello world!
53. What's the output?
function Car() {
this.make = 'Lamborghini';
return { make: 'Maserati' };
}
const myCar = new Car();
console.log(myCar.make);53. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
0%
A: "Lamborghini"
100%
B: "Maserati"
0%
C: ReferenceError
0%
D: TypeError
54. What's the output?
(() => {
let x = (y = 10);
})();
console.log(typeof x);
console.log(typeof y);54. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
100%
A: "undefined", "number"
0%
B: "number", "number"
0%
C: "object", "number"
0%
D: "number", "undefined"
55. What's the output?
class Dog {
constructor(name) {
this.name = name;
}
}
Dog.prototype.bark = function() {
console.log(`Woof I am ${this.name}`);
};
const pet = new Dog('Mara');
pet.bark();
delete Dog.prototype.bark;
pet.bark();55. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
100%
A: "Woof I am Mara", TypeError
0%
B: "Woof I am Mara", "Woof I am Mara"
0%
C: "Woof I am Mara", undefined
0%
D: TypeError, TypeError
56. What's the output?
const set = new Set([1, 1, 2, 3, 4]);
console.log(set);
56. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
0%
A: [1, 1, 2, 3, 4]
0%
B: [1, 2, 3, 4]
0%
C: {1, 1, 2, 3, 4}
100%
D: {1, 2, 3, 4}
57. What's the output?
// counter.js
let counter = 10;
export default counter;
// index.js
import myCounter from './counter';
myCounter += 1;
console.log(myCounter);
58. What's the output?
const name = 'Lydia';
age = 21;
console.log(delete name);
console.log(delete age);
58. What's the output?
Javob variantlari:
Javob variantlari:
Anonymous Quiz
100%
A: false, true
0%
B: "Lydia", 21
0%
C: true, true
0%
D: undefined, undefined
59. What's the output?
const numbers = [1, 2, 3, 4, 5];
const [y] = numbers;
console.log(y);