⭐ FSJS JavaScript Basics ⭐

Create a variable.js file and declare variables and assign string, boolean, undefined and null data types, Display all the value with there type.

number

let length = 16;
let weight = 7.5;

Strings

let color = "Yellow";
let lastName = "Johnson";

Booleans

let x = true;
let y = false;

null

let isPrime = null;
console.log(isPrime);

undefined

let name;
console.log(name);

Object:

const person = {firstName:"John", lastName:"Doe"};

Array object:

const cars = ["Saab", "Volvo", "BMW"];

Date object:

const date = new Date("2022-03-25");

Declare variables to store your first name, last name, marital status, country and age and display them using interploation method.

let firstName = 'Pranav'; // first name of a person
let lastName = 'Shimpi';   // last name of a person
let country = 'India';    // country
let city = 'Nashik';      // capital city
let age = 22;              // age in years
let isMarried = false;

console.log(`Full Name: ${firstName} ${lastName}\nCountry: ${country}\nCity: ${city}\nAge: ${age}\nMarried?: ${isMarried}\n`);

Decalre a varibale and assign value to it and change all the string characters to capital letters using toUpperCase() method.

country = "India";
console.log(country.toUpperCase())

Check if the string contains a word Script using includes() method.

includes contain string search and position

let essay = `In programming, data types is an important concept.
To be able to operate on variables, it is important to know something about the type.
Without data types, a computer cannot safely solve this:`


console.log(essay.includes('able'));  //true

console.log(essay.includes(200)); //false

console.log(essay.includes(15)); //false

console.log(essay.includes('Engineering')); //false

console.log(essay.includes('able',20)); //true

console.log(essay.includes('able',120));  //false

Split the string into an array using split() method

let string = '30 Days Of JavaScript'

console.log(string.split())     // ["30 Days Of JavaScript"]
console.log(string.split(' '))  // ["30", "Days", "Of", "JavaScript"]

let firstName = 'India'

console.log(firstName.split())  [ 'India' ]
console.log(firstName.split(''))  [ 'I', 'n', 'd', 'i', 'a' ]  

let countries = 'Finland, Sweden, Norway, Denmark, and Iceland'

console.log(countries.split(','))  // ["Finland", " Sweden", " Norway", " Denmark", " and Iceland"]
console.log(countries.split(', ')) //  ["Finland", "Sweden", "Norway", "Denmark", "and Iceland"]

'Facebook, Google, Microsoft, Apple, IBM, Oracle, Amazon' split the string at the comma and change it to an array.

let companies = 'Facebook, Google, Microsoft, Apple, IBM, Oracle, Amazon'

console.log(companies.split(','));
[
  'Facebook',
  ' Google',
  ' Microsoft',
  ' Apple',
  ' IBM',
  ' Oracle',
  ' Amazon'
]

console.log(companies.split(', '));
[
  'Facebook',
  'Google',
  'Microsoft',
  'Apple',
  'IBM',
  'Oracle',
  'Amazon'
]

Use lastIndexOf to determine the position of the last occurrence of a script.

let firstDate = "Hi simaran, How are you simarna. Remembered simaran I asked to for a date at that they and we just laugh as if I was just asking for timepass?. So I want to clear it from my side It was not I really Like you simaran."

console.log(firstDate.lastIndexOf('simaran')); // 208

Use search to find the position of the first occurrence of the word because in the following sentence:'You cannot end a sentence with because because because is a conjunction'.

let sentence = 'You cannot end a sentence with because because because is a conjunction'

console.log(sentence.indexOf('because')); //31

Use trim() to remove any trailing whitespace at the beginning and the end of a string.

let string = '   I will crack this company   '
console.log(string.trim())
console.log(string.trim(' '))

Boolean value is either true or false.
- Write JavaScript statement which provide truthy value.

 true && "dog"
 // returns "dog"

 [] && "dog"
 // returns "dog"

- Write JavaScript statement which provide falsy value.

```
console.log(false && "dog");
// ↪ false

console.log(0 && "dog");
// ↪ false
```

Figure out the result of the following comparison expression first without using console.log(). After you decide the result confirm it using console.log()

- 4 > 3  True
- 4 >= 3 True
- 4 < 3 False
- 4 <= 3 False
- 4 == 4  True
- 4 === 4 True
- 4 != 4 False
- 4 !== 4 False
- 4 != '4' False
- 4 == '4' True
- 4 === '4' False

Find the length of python and jargon and make a falsy comparison statement.

let str1 = "python"
let str2 = "jargon"
console.log(str1.length !=  str2.length);

Use the Date object to do the following activities
```
const now = new Date()
```
- What is the year today?
```
console.log(now.getFullYear())
```
- What is the month today as a number?
```
console.log(now.getMonth())
```
- What is the date today?
```
console.log(now.getDate())
```
- What is the day today as a number?
```
console.log(now.getDate())
```
- What is the hours now?
```
now.getHours()
```
- What is the minutes now?
```
now.getMinutes() 
```
- Find out the numbers of seconds elapsed from January 1, 1970 to now.
```
const now = new Date()
console.log(now.getTime()) 
```
Write a script that prompt the user to enter base and height of the triangle and calculate an area of a triangle (area = 0.5 x b x h).

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <h1>Area of triangle</h1>

    <h2 id="base"></h2>
    <h3 id="height"></h3>
    <h1 id="area"></h1>


</body>
<script>
    const baseValue = prompt('Enter the base of a triangle: ', 2);
    console.log(baseValue);
    const heightValue = prompt('Enter the height of a triangle: ', 3);
    console.log(heightValue);

    document.getElementById('base').innerHTML = "base = " + baseValue;
    document.getElementById('height').innerHTML = "height = " + heightValue;

    const area = 0.5 * baseValue * heightValue;

    document.getElementById('area').innerHTML = "Area of Triangle = " + area;
</script>

</html>

Slope is m = (y2-y1)/(x2-x1). Find the slope between point (2, 2) and point(6,10)

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <h1>Slope</h1>
    <p id="x1"></p>
    <p id="y1"></p>
    <p id="x2"></p>
    <p id="y2"></p>
    <p id="demo"></p>
</body>
<script>
    let x1 = prompt("Enter x1: ")
    let y1 = prompt("Enter y1: ")
    let x2 = prompt("Enter x2: ")
    let y2 = prompt("Enter y2: ")

    function slope(x1, y1, x2, y2) {
        if (x2 - x1 !== 0) {
            slope = (y2 - y1) / (x2 - x1);
            console.log(slope);
            return slope
        } else {
            console.log("0");
            return 0;
        }
    }

    result = slope(x1, y1, x2, y2)

    document.getElementById("x1").innerHTML = "x1 = " + x1;
    document.getElementById("y1").innerHTML = "y1 = " + y1;
    document.getElementById("x2").innerHTML = "x2 = " + x2;
    document.getElementById("y2").innerHTML = "y2 = " + y2;

    document.getElementById("demo").innerHTML = "slope = " + result;
</script>

</html>

Get radius using prompt and calculate the area of a circle (area = pi x r x r) and circumference of a circle(c = 2 x pi x r) where pi = 3.14.

<script>
    const pi = 3.14;

    let r = prompt("Enter radius of circle: ",7);

    function Area(r) {
        return pi*r*r;
    }

    function Diameter(r) {
        return 2*r;
    }

    function Circumference(r) {
        return 2*pi*r;
    }


    let areaVal = Area(r)
    let circumferenceVal = Circumference(r)
    let diameterVal = Diameter(r)

    document.getElementById("radius").innerHTML = "radius = " + r;
    document.getElementById("area").innerHTML = "area = " + areaVal;
    document.getElementById("diameter").innerHTML = "diameter = " + diameterVal;

    document.getElementById("circumference").innerHTML = "circumference = " + circumferenceVal;
</script>

Create a human readable time format using the Date time object

YYYY-MM-DD HH:mm
DD-MM-YYYY HH:mm
DD/MM/YYYY HH:mm

showDateTime = () => {
    let date = new Date();
    let datee = date.getDate();
    let month = date.getUTCMonth();
    let year = date.getFullYear();
    let hour = date.getHours();
    let minutes = date.getMinutes();
    return `${datee}/${month + 1}/${year} ${hour}:${minutes} `
}
showDateTime();

function dateFormater(date, separator) {
  var day = date.getDate();
  // add +1 to month because getMonth() returns month from 0 to 11
  var month = date.getMonth() + 1;
  var year = date.getFullYear();

  // show date and month in two digits
  // if month is less than 10, add a 0 before it
  if (day < 10) {
    day = '0' + day;
  }
  if (month < 10) {
    month = '0' + month;
  }

  // now we have day, month and year
  // use the separator to join them
  return day + separator + month + separator + year;
}

var now = new Date();
console.log(dateFormater(now, '/'));
console.log(dateFormater(now, '-'));
console.log(dateFormater(now, '.'));

Output:

02/01/2023
02-01-2023
02.01.2023

now = new Date();
console.log(now.toDateString());  //Fri Dec 16 2022

Get user input using prompt(“Enter your age:”). If user is 18 or older , give feedback:'You are old enough to drive' but if not 18 give another feedback stating to wait for the number of years he needs to turn 18.

function validate(age){
  var ans;
  if(age>=18){
      ans= "You are old enough to drive";
  }else{
     let diff = 18 - age;
     ans = `You need to wait ${diff} more years for Driving Lisense`; 
  }
  return (ans);
}
    
var age=parseInt(prompt("Enter age"));
var status=validate(age);
document.write(status);

Even numbers are divisible by 2 and the remainder is zero. How do you check, if a number is even or not using JavaScript?

if(num % 2 == 0){
    console.log("even")
}

Write a code which can give grades to students according to theirs scores:
- 80-100, A
- 70-89, B
- 60-69, C
- 50-59, D
- 0-49, F

    function myGrading(score) {
    var gscore;

    switch(true) {
        case (score <= 100 && score >= 80):
        gscore = 'A';
            break;
        case (score <= 89 && score >= 70):
            gscore = 'B';
            break;
        case (score <= 69 && score >= 60):
            gscore = 'C';
            break;
        case (score <= 59 && score >= 50):
            gscore = 'D';
            break;
        case (score <= 49 && score >= 0):
            gscore = 'F';
            break;

        case (score > 100 && score < 0):
            gscore = 'INVALID SCORE';
            break; 

        default:
        return 'INVALID SCORE';
    }

    return gscore;
    }

    var output = myGrading(71);
    var output = myGrading(40);
    var output = myGrading(83);
    console.log(output);

Check if the season is Autumn, Winter, Spring or Summer. If the user input is :

September, October or November, the season is Autumn.
December, January or February, the season is Winter.
March, April or May, the season is Spring
June, July or August, the season is Summer

function checkSeason(month) {
    var season;
    month = month.toLowerCase();

    switch (true) {
        case (month == "september" || month == "october" || month == " november"):
            season = 'Autumn';
            break;
        case (month == "december" || month == "january" || month == " february"):
            season = 'Winter';
            break;
        case (month == "march" || month == "april" || month == "may"):
            season = 'Spring';
            break;
        case (month == "june" || month == "july" || month == " august"):
            season = 'Summer';
            break;

        default:
            return 'INVALID MONTH';
    }
    return season;
}

var output1 = checkSeason('January');
var output2 = checkSeason('MARCH');
var output3 = checkSeason('Spring');

console.log(output1); // Winter
console.log(output2); // Spring
console.log(output3); // INVALID MONTH

Write a program which tells the number of days in a month.

const getDays = (year, month) => {
    return new Date(year, month, 0).getDate();
};
const daysInSeptember = getDays(2021, 7); // Returns 31

Write a program which tells the number of days in a month, now consider leap year.

function numOfDays(year,month) {
    let ans;
    if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12){
        ans = `Number of days is 31`
    }
    else if ((month == 2) && ((year % 400 == 0) || (year % 4 == 0 && year % 100 != 0))) {
        ans = `Number of days is 29`
    } else if (month == 2) {
        ans = `Number of days is 28`
    } else{
        ans = `Number of days is 30`
    }
    return ans;
}

let val = numOfDays(2023, 1)
console.log(val)

Create a separate countries.js file and store the countries array in to this file, create a separate file web_techs.js and store the webTechs array in to this file. Access both file in main.js file
```
// In main.js

import countries from "./countries.js";
import web_techs from "./web_techs.js";


console.log(countries);
console.log(web_techs);
```

In the following shopping cart add, remove, edit items => const shoppingCart = ['Milk', 'Coffee', 'Tea', 'Honey']

add 'Meat' in the beginning of your shopping cart if it has not been already added
add Sugar at the end of you shopping cart if it has not been already added
remove 'Honey' if you are allergic to honey
modify Tea to 'Green Tea'

const shoppingCart = ['Milk', 'Coffee', 'Tea', 'Honey']

// 1

shoppingCart.unshift("Meat")

// 2

let lastIndex = shoppingCart.length - 1;
let lastIndexVal = shoppingCart[lastIndex]

if(lastIndexVal!="Sugar"){
shoppingCart.push("Sugar");
}

console.log(shoppingCart);

// 3

let allergicToHoney = true;

let pattern = "Honey"

if(allergicToHoney){
shoppingCart.filter(ele => {
    if(ele!=pattern){
    console.log(ele);
    }
})

}

console.log(shoppingCart);

// 4

let newItem = shoppingCart.indexOf("Tea")
shoppingCart[newItem] = "Green Tea"
console.log(shoppingCart);

In countries array check if 'Ethiopia' exists in the array if it exists print 'ETHIOPIA'. If it does not exist add to the countries list.

let isPresent = console.log( countries.indexOf('Ethiopia'));

if(!isPresent){
countries.push("Ethiopia".toUpperCase())
}

console.log(countries);

The following is an array of 10 students ages:

const ages = [19, 22, 19, 24, 20, 25, 26, 24, 25, 24]

Sort the array and find the min and max age

console.log(ages.sort());
console.log(Math.max(...ages));
console.log(Math.min(...ages));

Find the median age(one middle item or two middle items divided by two)

const ages = [19, 22, 19, 24, 20, 25, 26, 24, 25, 24]

const median = ages => {
  const mid = Math.floor(ages.length / 2),
    nums = [...ages].sort((a, b) => a - b);
  return ages.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2;
};

console.log(median(ages));

Find the average age(all items divided by number of items)

let len = ages.length;
let sum = 0;
ages.forEach((ele)=>{
sum = sum + ele;
})
let average = sum / len;
console.log(average);

Find the range of the ages(max minus min)

let range = Math.max(...ages) - Math.min(...ages)
console.log(range);

Compare the value of (min - average) and (max - average), use abs() method

console.log(maxx - average)
console.log(minn - average)
console.log(Math.abs(maxx - average))
console.log(Math.abs(minn - average))

Use for loop to iterate from 0 to 100 and print only prime numbers

for(let i = 0; i <100; i++){
  let flag = 0;
  for(let j = 2 ;j < i; j++){
    if(i%j == 0){
      flag = 1;
      break;
    }
  }

  if(i > 1 && flag == 0){
    console.log(i);
  }

}

Use for loop to iterate from 0 to 100 and print the sum of all evens and the sum of all odds.

let i;
let sumE = 0;
let sumO = 0;

for (i = 0; i <= 100; i++) {
  i % 2 === 0 ? (sumE += i) : (sumO += 1);
}

console.log(sumE, sumO);

Write a script which generates a random hexadecimal number.

const random_hex_color_code = () => {
  let n = (Math.random() * 0xfffff * 1000000).toString(16);
  return '#' + n.slice(0, 6);
};

console.log(random_hex_color_code())

Sort the webTechs array and mernStack array
```
webTechs.sort();
mernStack.sort();
```

// countries Array : https://gist.github.com/incredimike/1469814

Array Questions

Extract all the countries contain the word 'land' from the countries array and print it as array

let countWithoutLand = []
let countWithLand = []
for (let i = 0; i < countries.length; i++) {
    if (countries[i].includes("LAND")) {
        countWithLand.push(countries[i]);
    } else {
        countWithoutLand.push(countries[i])
    }
}

Find the country containing the hightest number of characters in the countries array

let prevLen = 0;
let longestChar;
countryList.forEach((country) => {
if (country.length > prevLen) {
    prevLen = country.length;
    longestChar = country
}
});

console.log(longestChar);

Extract all the countries containing only four characters from the countries array and print it as array

countryList.forEach((country) => {
    if (country.length === 4) {
        console.log(country);
    }
});

Extract all the countries containing two or more words from the countries array and print it as array

const newArr = [];

countryList.forEach((ele) => {
if (ele.length > 10) {
    newArr.push(ele);
}
});

console.log(newArr);

Reverse the countries array and capitalize each country and stored it as an array

const newArr = [];

countryList.forEach((ele) => {
if (ele) {
    newArr.unshift(ele.toUpperCase());
}
});

console.log(newArr);

Body mass index(BMI) is calculated as follows: bmi = weight in Kg / (height x height) in m2. Write a function which calculates bmi. BMI is used to broadly define different weight groups in adults 20 years old or older.Check if a person is underweight, normal, overweight or obese based the information given below.
- The same groups apply to both men and women.
- Underweight: BMI is less than 18.5
- Normal weight: BMI is 18.5 to 24.9
- Overweight: BMI is 25 to 29.9
- Obese: BMI is 30 or more
Solution : VIEW CODE / LIVE PREVIEW
Linear equation is calculated as follows: ax + by + c = 0. Write a function which calculates value of a linear equation, solveLinEquation.

Write a functions which checks if all items are unique in the array.

const allUnique = arr => arr.length === new Set(arr).size;
console.log(allUnique([1,2,3,4,5,6]))   // true
console.log(allUnique([1,2,3,4,5,6,3]))  // false

⭐ FSJS JavaScript Advance Questions⭐

Create an object literal called personAccount. It has firstName, lastName, incomes, expenses properties and it has totalIncome, totalExpense, accountInfo,addIncome, addExpense and accountBalance methods. Incomes is a set of incomes and its description and expenses is a set of incomes and its description.

    let personalAccount = {
    firstName: "Ram",

    lastName: "Pyare",

    income: [20000, "mysalary"],

    expenses: [500, "Medicine"],

    flatIncome: [],
    flatExpense: [],

    get getIncome() {
      this.flatIncome = [].concat(...this.income);
      return `All Incomes : ${this.flatIncome}`;
    },

    get getExpense() {
      this.flatExpense = [].concat(...this.expenses);
      return `All Expenses : ${this.flatExpense} `;
    },

    get getTotalIncome() {
      let totalIncome = 0;
      this.flatIncome.forEach((ele) => {
        if (typeof ele === "number") {
          totalIncome += ele;
        }
      });
      return `${totalIncome}`;
    },

    get getTotalExpenses() {
      let totalExpense = 0;
      this.flatExpense.forEach((ele) => {
        if (typeof ele === "number") {
          totalExpense += ele;
        }
      });
      return `${totalExpense}`;
    },

    get getAccountInfo() {
      return `Name = ${this.firstName} ${this.lastName} \nTotal Income = ${this.getTotalIncome} \nTotal Expenses = ${this.getTotalExpenses}`;
    },

    set setAddIncome(val) {
      let x = this.income.push(val);
      // return x;
    },

    set setAddExpense(val) {
      let x = this.expenses.push(val);
      // return x;
    },

    get getAccountBalance() {
      let balance = this.getTotalIncome - this.getTotalExpenses;
      return `Balance : ${balance}`;
    },
  };

  personalAccount.setAddIncome = [5000, "Bonus"];

  personalAccount.setAddIncome = [2500, "HRA"];

  personalAccount.setAddIncome = [400, "PF"];

  personalAccount.setAddExpense = [100, "chocolate"];

  personalAccount.setAddExpense = [20, "Pani puri"];

  personalAccount.setAddExpense = [2500, "Grocery"];

  personalAccount.setAddExpense = [1200, "shopping"];

  console.log(personalAccount.getIncome);

  console.log(personalAccount.getExpense);

  console.log( personalAccount.getAccountInfo);

  console.log( personalAccount.getAccountBalance);

a. Create a function called signUp which allows user to add to the collection. If user exists, inform the user that he has already an account. b. Create a function called signIn which allows user to sign in to the application


const users = [
{
    _id: "ab12ex",
    username: "Alex",
    email: "alex@alex.com",
    password: "123123",
    createdAt: "08/01/2020 9:00 AM",
    isLoggedIn: false,
  },
  {
    _id: "fg12cy",
    username: "Asab",
    email: "asab@asab.com",
    password: "123456",
    createdAt: "08/01/2020 9:30 AM",
    isLoggedIn: true,
  },
  {
    _id: "zwf8md",
    username: "Brook",
    email: "brook@brook.com",
    password: "123111",
    createdAt: "08/01/2020 9:45 AM",
    isLoggedIn: true,
  },
  {
    _id: "eefamr",
    username: "Martha",
    email: "martha@martha.com",
    password: "123222",
    createdAt: "08/01/2020 9:50 AM",
    isLoggedIn: false,
  },
  {
    _id: "ghderc",
    username: "Thomas",
    email: "thomas@thomas.com",
    password: "123333",
    createdAt: "08/01/2020 10:00 AM",
    isLoggedIn: false,
  },
];


function signUp(_id, username, email, password, createdAt, isLoggedIn) {
let flag = 0;
for (const ele of users) {
  if (ele.email === email) {
    flag = 1;
    break;
  } else {
    flag = 0;
  }
}

if (flag == 0) {
  users.push({
    _id,
    username,
    email,
    password,
    createdAt,
    isLoggedIn,
  });
  console.log(users);
} else {
  console.log("user already exists");
}
}

//signUp("Af1234", "shyam", "123@mba.com", "123456", "17/02/2022 12:00 AM", false);

function signIn(email, password) {
for (const ele of users) {
  if (ele.email === email && ele.password === password) {
    console.log(`Hi ${ele.username}, you are successfully loggedIn....`);
    ele.isLoggedIn = true;
    console.log(ele);
    break;
  } else if (ele.email === email && ele.password !== password) {
    console.log("You have entered an invalid email or password.....");
    break;
  } else if (ele.email !== email && ele.password === password) {
    console.log("You have entered an invalid email or password.....");
    break;
  } else if (ele.email !== email && ele.password !== password) {
    console.log("Unauthorized User Try SignUp....");
    break;
  }
}
}

// signIn("alex@alex.com","123456")

The products array has three elements and each of them has six properties.

     const products = [
    {
      _id: "eedfcf",
      name: "mobile phone",
      description: "Huawei Honor",
      price: 200,
      ratings: [
        { userId: "fg12cy", rate: 5 },
        { userId: "zwf8md", rate: 4.5 },
        { userId: "zwf8md", rate: 3.5 },
        { userId: "zwf8md", rate: 4.15 },
      ],
      likes: ["adafe", "ar2423", "tsdgzd"],
    },
    {
      _id: "aegfal",
      name: "Laptop",
      description: "MacPro: System Darwin",
      price: 2500,
      ratings: [],
      likes: ["fg12cy"],
    },
    {
      _id: "hedfcg",
      name: "TV",
      description: "Smart TV:Procaster",
      price: 400,
      ratings: [{ userId: "fg12cy", rate: 5 }],
      likes: ["fg12cy"],
    },
  ];

a. Create a function called rateProduct which rates the product

const rateProduct = (name, rate) => {
 products.forEach((product) => {
   if (product.name.toLocaleLowerCase().includes(name)) {
     let chars = "0123456789abcdefghiklmnopqrstuvwxyz";
     let id = [];

     for (let i = 0; i < 6; i++) {
       id.push(chars[Math.floor(Math.random() * chars.length)]);
     }
     id = id.join("");

     product.ratings.push({
       userId: id,
       rate: rate,
     });
     console.log("filter");
   } else {
     console.log(`No product to rate`);
   }
 });
};

// rateProduct("laptop", 4.1);
// rateProduct("laptop", 4);

b. Create a function called averageRating which calculate the average rating of a product

const avgRating = (name) => {
 let avg = 0;
 let product;

 for (const prod of products) {
   if (prod.name.toLocaleLowerCase() === name.toLocaleLowerCase()) {
     product = prod;
     // console.log(product);
   }
 }

 for (const user of product.ratings) {
   avg += user.rate;
 }

 avg /= product.ratings.length;

 console.log(`\n Avg Rating of ${name} =  ` + avg.toFixed(2));
 };
 // avgRating("tv");

Create a function called likeProduct. This function will helps to like to the product if it is not liked and remove like if it was liked.

   let likeProduct = (name, id) => {
    let product, index;
    for (let i = 0; i < products.length; i++) {
      if (products[i].name.toLowerCase() == name.toLowerCase()) {
        product = products[i];
      } 
    }

    index = product.likes.indexOf(id);

    if (index == -1) {
      product.likes.push(id);

      console.log(`liked ${name} by user ` + product.likes.slice(-1));
    } else {
      console.log(`Dislike ${name} by user ` + product.likes.splice(index, 1));
    }
  };

  likeProduct("Mobile phone", "fg12cy");

  likeProduct("Mobile phone", "ar2423");

  likeProduct("Laptop", "abcd123");

Create an empty object called dog Print the the dog object on the console

Add name, legs, color, age and bark properties for the dog object.

The bark property is a method which return woof woof

Get name, legs, color, age and bark value from the dog object

Set new properties the dog object: breed, getDogInfo

const dog ={
    get getDogInfo(){
        return `name = ${this.name}, color = ${this.color}, breed = ${this.breed}`;
    },

    set dogInfo(value){
        dog.breed = value;
        }   
}

    dog.name = "biscuit"
    dog.age = "0.4";
    dog["legs"] = 4;
    dog["color"] = "brown";
    dog["bark"] = "woof woof"

    dog.doesBark = function (){
      return this.bark;
    }

    // console.log(dog);
    console.log(dog.doesBark);

    // accessing as a function
    console.log(dog.doesBark()); // accessing as a function 

    // accessing as a getters
    console.log(dog.NameColor); // using getter method accessing as a  property 

    // setters 
    dog.dogInfo = "Pandikona"

    console.log(dog.getDogInfo);

    console.log(dog);

Explain the difference between forEach, map, filter, and reduce. Article
Define a callback function before you use it in forEach, map, filter or reduce.

A callback function is a function passed into another function as an argument, 
which is then invoked inside the outer function to complete some kind of routine or action.


function greeting(name) {
  alert(`Hello, ${name}`);
}

function processUserInput(callback) {
  const name = prompt("Please enter your name.");
  callback(name);
}

processUserInput(greeting);

Use forEach to console.log each name in the names array.
Use forEach to console.log each country in the countries array.
Use forEach to console.log each number in the numbers array.

names.forEach(ele => {
  console.log(ele);
})

countries.forEach(ele => {
  console.log(ele);
})

numbers.forEach(ele => {
  console.log(ele);
})

Use map to create a new array by changing each country to uppercase in the countries array.
Use map to create an array of countries length from countries array.
Use map to create a new array by changing each number to square in the numbers array
Use map to change to each name to uppercase in the names array old syntax
Use map to map the products array to its corresponding prices.

//1
let country = countries.map((ele) => ele.toUpperCase());
console.log(country);

//2
let country = countries.map((ele) => ele.length);
console.log(country);

//3
let number = numbers.map((ele => ele*ele))
console.log(number);

//4
let name = names.map(function(ele) {
  return ele.toUpperCase();
})
console.log(name);

//5
let product = products.map((ele)=>{
  return `name = ${ele.product} & price = ${ele.price}`;
})
console.log(product);

Use filter to filter out countries containing land.
Use filter to filter out countries having six character.
Use filter to filter out countries containing six letters and more in the country array.
Use filter to filter out country start with 'E';
Use filter to filter out only prices with values.

//1  
let filt = countries.filter(country => {
  return country.toLowerCase().includes('land')
})
console.log(filt);

//2
let filt = countries.filter(country => {
  return (country.length == 6)
})
console.log(filt);

//3
let filt = countries.filter(country => {
  return (country.length >= 6)
})
console.log(filt);

//4
let filt = countries.filter(country => {
  return country[0].toLowerCase() ===  "i"
  // return country.toLowerCase().startsWith('s')
})
console.log(filt);

//5
let filt = products.filter(product => {
  return product.price > 0;
})
console.log(filt);

Declare a function called getStringLists which takes an array as a parameter and then returns an array only with string items.

const getStringLists = (arr) => {
  let onlyString = arr.filter(ele => {
    return typeof ele === 'string';
  })
  return onlyString
}

let nn = getStringLists(["victor", 3, 5, "kenneth","57"]);
console.log(nn);

Use reduce to sum all the numbers in the numbers array.
Use reduce to concatenate all the countries and to produce this sentence: Estonia, Finland, Sweden, Denmark, Norway, and IceLand are north European countries

//1
let sum = numbers.reduce((accumulator, currentValue)=>{
  return accumulator + currentValue;
})

//2
let joinCountries = countries.reduce((accumulator, currentValue) => {
  return accumulator+", "+currentValue;
})
console.log(joinCountries + ' are north European countries');

Explain the difference between some and every
Use some to check if some names' length greater than seven in names array
Use every to check if all the countries contain the word land

//1
every checks if all elements in an array are similar in all aspects
some checks if some elements are elements are similar in one aspect

//2 
let name = names.some(ele => {
  return ele.length > 6;
})

console.log(name);

//3 
let name = countries.some(ele => {
  return ele.toLowerCase().includes('land');
})

console.log(name);

Explain the difference between find and findIndex.
Use find to find the first country containing only six letters in the countries array
Use findIndex to find the position of the first country containing only six letters in the countries array
Use findIndex to find the position of Norway if it doesn't exist in the array you will get -1.
Use findIndex to find the position of Russia if it doesn't exist in the array you will get -1.

//1
find returns the first element which satisfies the condition
findIndex returns the first index elemnt whic satisfiy the condition

//2
let check = countries.find(ele => {
  return ele.length > 6;
})

console.log(check);

//3
let check = countries.findIndex(ele => {
  return ele.length === 6;
})

console.log(check);

//4 
let firstIndexPosNorwayExist = countries.findIndex(country => {
  return country.includes("Norway")
});
console.log(firstIndexPosNorwayExist);

//5
let firstIndexPosNorwayExist = countries.findIndex(country => {
  return country.includes("Russia")
});
console.log(firstIndexPosNorwayExist);

create an empty set
Create a set containing 0 to 10 using loop
Remove an element from a set
Clear a set
Create a set of 5 string elements from array
Create a map of countries and number of characters of a country

//1
const companies = new Set();
console.log(companies);

//2
let set1 = new Set();
for (let i = 0; i < 10; i++) {
  set1.add(i);
}

//3
const a = [4, 5, 8, 9];

let set2 = new Set(a);
console.log(set2);

set2.delete(9);
console.log(set2);

//4
set2.clear();
console.log(set2);

//5
let city = ["pune", "mumbai", "banglore", "delhi", "nashik"];
let citySet = new Set();
city.forEach((city) => {
  citySet.add(city);
});
console.log(citySet);

//6
const countries2 = ["Finland", "Sweden", "Turkistan", "USA"];

let countriesLength = new Set();
for (let i = 0; i < countries2.length; i++) {
  countriesLength.add(countries2[i]);
  countriesLength.add(countries2[i].length);
}
console.log(countriesLength);

Destructure and assign the elements of constants array to e, pi, gravity, humanBodyTemp, waterBoilingTemp.
Destructure and assign the elements of countries array to fin, est, sw, den, nor
Destructure the rectangle object by its properties or keys.

//1
const constants = [2.72, 3.14, 9.81, 37, 100]
let [e,pi,gravity,humanBodyTemp, waterBoilingTemp] = constants

console.log(e);
console.log(pi);
console.log(gravity);
console.log(waterBoilingTemp);

//2
let [fin, est, sw, den, nor] = countries
console.log(den);

//3
const rectangle = {
  width: 20,
  height: 10,
  area: 200,
  perimeter: 60
}

let { width, height, area, perimeter } = rectangle

console.log(width, height, area, perimeter)

let { width: w, height: h, area: a, perimeter: p } = rectangle

console.log(w, h, a, p)

Iterate through the users array and get all the keys of the object using destructuring
Find the persons who have less than two skills

const users = [
  {
    name: "Brook",
    scores: 75,
    skills: ["HTM", "CSS", "JS"],
    age: 16,
  },
  {
    name: "Alex",
    scores: 80,
    skills: ["HTM", "CSS", "JS"],
    age: 18,
  },
  {
    name: "David",
    scores: 75,
    skills: ["HTM", "CSS"],
    age: 22,
  },
  {
    name: "John",
    scores: 85,
    skills: ["HTML"],
    age: 25,
  },
  {
    name: "Sara",
    scores: 95,
    skills: ["HTM", "CSS", "JS"],
    age: 26,
  },
  {
    name: "Martha",
    scores: 80,
    skills: ["HTM", "CSS", "JS"],
    age: 18,
  },
  {
    name: "Thomas",
    scores: 90,
    skills: ["HTM", "CSS", "JS"],
    age: 20,
  },
];


//1
for (const {name,scores,skills,age} of users) {
  console.log(name,scores,skills,age);
}

//2
for (const { skills } of users) {
  if (skills.length <= 2) {
    console.log(skills);
  }
}

for (let{name, scores, skills, age } of users) {
  if (skills.length < 3) {
    console.log(name, scores, skills, age);
  }
}

Create a closure

function numberGenerator() {
  
  var num = 1;
  function checkNumber() { 
    console.log(num);
  }
  num++;
  return checkNumber;
}

var number = numberGenerator();
number();

PranaV-Shimpi / JavaScript-Basics

⭐ FSJS JavaScript Basics ⭐

⭐ FSJS JavaScript Advance Questions⭐

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