pratimaroy/mock-interview-trivia-questions

This is the List of All Trivia Questions and where they are being used

Question	Associated Lesson
What is the difference between an parameter and and argument?	Control Flow
What is the difference between var, const, and let	Control Flow
Within a function, what is the difference between return and console.log()	Control Flow
Code block, see below	Control Flow
Code block, see below	Control Flow
What is the difference between =, ==, and ===	Math
What is NaN?	Math
Is NaN == NaN true or false, why?	Math
Is 'McDonalds' > 'Burger King' - true, false or an error? Why?	Strings & RegEx
What are the differences between a single quote, double quote, smart quote, and backtick?	Strings & RegEx
What is the difference between a and 'a' in JavaScript?	Strings & Regex
What is the difference between a function declaration and a function expression?	Errors
What is one difference between an arrow function and a function declaration?	Errors
Can a function expression be an anonymous function?	Errors
Can a function declaration be an anonymous function?	Errors
Is an arrow function a function declaration or function expression?	Errors
What is the first index position of an array in JS?	Arrays & Callbacks
What is a primitive data type?	Arrays & Callbacks
Is an array a primitive data type?	Arrays & Callbacks
What is the difference between: for (let i = 0; i < 5; i++) and for (i = 0; i < 5; i++ )	Arrays & Callbacks
What is a higher order function?	Working with Objects
What is a callback function?	Working with Objects
What is the spread/rest ... operator? What does it do?	Big O
Code block, see below	Big O
What is the difference between 1000 and 1_000?	Recursion
What does parseInt() do?	Recursion
What does parseFloat() do?	Recursion
What does Number() do?	Recursion
What does isNaN() do?	Recursion
In JavaScript ?. is the symbol for optional chaining. What is optional chaining and where/when would you use it?	OOP
Code block, see below	OOP
In JavaScript, what does the keyword static inside of a class do?	OOP 2
Why would we use the keyword static? What problem does it solve?	OOP 2
none - pre-reading instead	Linked Lists
none - pre-reading instead	Stacks & Queues
none - pre-reading instead	Trees
Code block, see below	searching algos 1
Code block, see below	searching algos 1
	searching algos 1
if const declares a constant variable, why can you declare an array and still add/change and delete elements?	searching algos 2
Code block, see blow	searching algos 2
	searching algos 2
	hash tables
	hash tables

Evaluate Code Block:

Control Flow

Do these code blocks return the same thing? What is different about them?

const findFirstEvenNum = (arr) => {
  let num = 0;
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] % 2 === 0) {
      num = arr[i];
      break;
    }
  }
  return num;
};

const findFirstEvenNum = (arr) => {
  for (let i = 0; i < arr.length; i++) {
    if (arr[i] % 2 === 0) {
      return arr[i];
    }
  }
};

Big O

Look at the following output

const numbers = [1, 2, 3, 4, 5];
const printItems = (arr) => {
  for (let item in arr) {
    console.log(item);
  }
};

console.log(printItems(numbers));

The output is

1
2
3
4
5
undefined

Why is the last line undefined?

OOP

1. What is wrong with the following code?

const delete = (item) => {
  console.log('item was deleted')
}

2. What will the value be for color, after the following code runs, for the following instances of Car:

• newCar
• secondNewCar

class Car {
  constructor(brand, model, color = "soul red") {
    this.brand = brand;
    this.model = model;
    this.color = color;
  }
}

const newCar = new Car("Mazda", "MX-30");
const secondNewCar = new Car("Porche", "Vintage Carrera", "Yellow");

Search Algos

What is the value of newArr

const newArr = [...[1, 2, 3], ...[4, 5, 6]];

Search Algos 2

What is the final value of a and b

let a = 10;
let b = 20;

[a , b] = [b, a];

Is there any difference if the code is written like so?

const a = 10;
const b = 20;

[a , b] = [b, a];