Basic 10 Problems Solving With JavaScript That should JavaScript Developer Practice

JavaScript consists of a standard library of objects, i.e., Array, Math, and Date, and a core set of programming language elements such as operators, statements, and control structures.

javascript problem solving

JavaScript is an interpreted, lightweight, or just-in-time (JIT) compiled programming language with first-class functions. Every type of problems can be solved through this language.

Today I am going to solve the best 10 problems with the help of JavaScript as well.

Let’s get started!

1. Find the largest element of an array

const arr = [1, 5, 7, 3, 11, 9, 99, 57];
let largest= 0;

for (i = 0; i <= largest; i++){
    if (arr[i]>largest) {
        largest=arr[i];
    }
}

console.log(largest); // 99

2. Find the sum of all number in an array

// Using reduce array helper method
const arr = [5, 6, 7, 9, 11]
const sum = arr.reduce((a, b) => a + b, 0)
console.log(sum); // 38

3. Remove duplicate item from an array

// Using Set method
let names = ['Mostafa', 'Mahmud', 'Shams', 'Mostafa', 'Sadia'];
let uniqueNames= [...new Set(names)];
console.log(uniqueNames);
// ['Mostafa', 'Mahmud', 'Shams', 'Sadia']

4. Count the number of words in a string

// Using match function with regex
const words = "I love JavaScript";
let wordsCount = words.match(/(\w+)/g).length;
console.log(wordsCount);
// 3

5. Reverse a string

// Using for loop with variable decreament from last to first
function reverseStr(str) {
   let newStr = "";
   for (let i = str.length - 1; i >= 0; i--) {
      newStr += str[i];
   }
   return newStr;
}
console.log(reverseStr('Bangladesh'));
// hsedalgnaB

6. Calculate Factorial of a number using for loop

function factorial(num) {
    // 0 or 1 factorial is always 1
    if (num === 0 || num === 1)
       return 1;
    for (let i = num - 1; i >= 1; i--) {
       num *= i;
    }
    return num;
}
console.log(factorial(5));
// 120

7. Calculate Factorial of a number using a while loop

function factorial(num) {
  let result = num;
  if (num === 0 || num === 1) 
     return 1; 
  // When num is less than 1, looping is stopped
  while (num > 1) { 
     num--;
     result *= num;
  
}
  return result;
}
factorial(5); // 120

8. Calculate Factorial in a Recursive function

// factorial function runs itself until finished
function factorial(x)  {
     
    if (x === 0)  {     
        return 1;  
    }   
    return x * factorial(x-1);
} 
console.log(factorial(5)); // 120

9. Create a Fibonacci Series using a for loop

let fibo = function(num) {
   let a = 0, b = 1, fib = 1;
   for(let i = 2; i <= num; i++) {
      fib = a + b;
      a = b;
      b = fib;
   }
   return fib;
};
console.log(fibo(5)) // 5
console.log(fibo(10)) // 55
console.log(fibo(20)) // 6765

10. Check whether a number is a Prime Number or not

// Using ES6 syntax
const isPrime = num => {
   for(let i = 2; i < num; i++) {
     if(num % i === 0) return false;
   }
   return num > 1;
}
console.log(isPrime(10)); // false
console.log(isPrime(5)); // true