JavaScript Day 2

Which of the following is a correct way to declare a variable in JavaScript?

• variable name = 'John';

• let name = 'John';

• const name = 'John';

• var name 'John';

Which of the following is not a primitive data type in JavaScript?

• Number

• String

• Object

• Boolean

What is the result of the following expression: '5' + 3?

• 8

• 53

• 35

• None

What will be the output of the following code?

var x = 10;

if (true) {

var x = 20;

}

console.log(x);

• 10

• 20

• Undefined

• Null

What will be the output of the following code?

let y = 10;

if (true) {

let y = 20;

}

console.log(y);

• 10

• 20

• Error

• Undefined

Which method is used to convert all the lowercase letters in a string to uppercase in JavaScript?

• toLowerCase()

• toUpperCase()

• capitalize()

• uppercase()

Which of the following declarations will result in an error if the variable is reassigned or redeclared?

• var name = 'John';

• let name = 'John';

• const name = 'John';

• var name;

  name = 'John';

What is the output of the following code?

let value;

console.log(value);

• undefined

• null

• 0

• Reference Error

Which data type is used to represent true or false values in JavaScript?

• Number

• String

• Boolean

• Object

Can we name the 1st letter of variable with numbers?

• Yes

• Depends

• No