180-191

What will be the output of the following code?

    ```javascript

    let num = 10;

    console.log(num++);

    ```

• 10 \

    

• 11  \

• 9 \

    

• Error

What is the purpose of the `Array.prototype.push()` method in JavaScript?

• Removes the first element from an array

• Adds one or more elements to the end of an array 

• Reverses the order of the elements in an array

    

• Sorts the elements of an array

Which of the following is not a valid way to declare a JavaScript function?

• `function myFunction() {}`

• `const myFunction = function() {}`

• `let myFunction = () => {}`

• `var myFunction = () => {}` 

What does the following code snippet do?

    ```javascript

    const person = {

        name: 'John',

        age: 30,

        greet() {

            console.log(`Hello, my name is ${this.name} and I'm ${this.age} years old.`);

        }

    };

    person.greet();

    ```

•  Declares a function named `greet`

• Logs "Hello, my name is John and I'm 30 years old." to the console 

•    c) Defines an array named `person`

• Throws an error

What does the `Array.prototype.filter()` method do in JavaScript?

• Modifies the original array

• Creates a new array with elements that pass a test specified by a function  

• Removes elements from an array

• Adds elements to an array

What will be the output of the following code?

    ```javascript

    const array = [1, 2, 3, 4, 5];

    const doubledArray = array.map(item => item * 2);

    console.log(doubledArray);

• [2, 4, 6, 8, 10]  

• [1, 2, 3, 4, 5]

• [1, 4, 9, 16, 25]

• Error

What does the `Object.keys()` method return in JavaScript?

• An array of a given object's property names 

• The number of properties in an object

• An array of a given object's property values

• The prototype of an object

What is the keyword used to declare a variable in JavaScript?

• `var`

   

• `let`

• `const`

    

• `variable`

What will be the type of the following expression in JavaScript: `typeof([])`?

• `array`

   

• `object`

    

• `array`

    

• `undefined`

Which keyword is used to define a class in JavaScript?

• `class`

    

• `prototype`

• `function`

• `object`