Frontend Summer Internship Quiz-9

What will this function return if you pass an Object?

Please note: Object.keys(mObj) will return an array of all the keys in "mObj" object.

• • List of keys

• • Error

• • Copy of that object

• • None of the above

What will be printed in the console?

 

console.log(parseInt(false))

console.log(Number(false))

• • 0 and 0

• • NaN and NaN

• • NaN and 0

• • Error

What will be printed in the console?

 

var num1 = 100;

 

var result = num1 > 50 ? (num1+10) < 100 ? (num1 + 20) : (num1 + 50) < 200 ? (num1 + 500) : (num1 + 200) : num1;

console.log(result)

• • 120

• • 150

• • 100

• • 600

What will be printed in the console?

 

console.log(num1);

num1 = 10;

console.log(num1);

var num1;

• • Error

• • undefined and 10

• • undefined and undefined

• • 10 and 10

What will be the output?

var num1 = 10;

var num2 = 20;

var num3 = 30;

var sum1 = ++num1 + num2++ + num3++;

var sum2 = num1++ + ++num2 + ++num3;

var sum3 = num1++ + num2++ + num3++;

console.log(sum1 + sum2 + sum3)

• • 190

• • 192

• • 195

• • 196

What will be the output of the following code?(delete operator removes a property from an object)

var output = function (x) {

delete x;

return x;

};

console.log(output(9));

• • Undefined

• • 9

• • null

• • Error: Can not reference the variable x

What will be the output of the following code?

var dummy = true;

console.log(dummy + 0);

console.log(dummy + "xyz");

console.log(dummy + true);

console.log(dummy + false);

• • true, "truexyz", "truettrue", "truefalse"

• • 1, "truexyz", 2, 1

• • true, "truexyz", true , true

• • 1, "truexyz", 1, 0

How do you check if a 'key' exists in an object?

• • (obj["key"] !== undefined)

• • (obj.key !== undefined)

• • Both A and B

• • None of the above

The slice() method mutates the original array and it returns the subset as new array.

• • True

• • False

Splice method does not mutate the original array and returns the deleted array.

• • True

• • False