JavaScript Evaluation 1

Q :1 1. Check prime number?

Algorithm

• Step 1 : Start the process.

• Step 2 : check the given number num<0,

  • Step 2.1 : Print "Prime number must be positive integers ".

• Step 3 : Check wheather the given number is (num===0 || num===1)

  • Step 3.1 : Print "Entered number is Neither prime nor composite".

• Step 4 : Check number is wheather (n===2)

  • Step 4.1 Print " Entered Number is prime" .

• Step 5 : else the above conditions fails, check the factors for given number:

     for(let i=1;i<=num;i++){
      if(num%i===0)
      count++;
  

  • Step 5.1 : If the counnt value is (count===2) , then Print "Prime" or Print "Not prime";

• Step 6 : Stop the process.

Program :

function isPrime(num){
   let count=0;
    if(num<0) {
        console.log("Prime number must be positive integers ");
    }
  else if(num===0 || num===1){
      console.log( " Entered number is Neither prime nor composite" ) ;
  }
  else if( num===2 )
  {
         console.log( " Entered Number is prime" ) ;
  }

  else
  {
      for(let i=1;i<=num;i++){
          if(num%i===0)
          count++;
      }
       (count ===2 ) ?  console.log("Prime") : console.log( "Not prime" );
}
}
isPrime(0);
isPrime(1);
isPrime(2);
isPrime(91);
isPrime(-67);

• Output:

 Entered number is Neither prime nor composite
 Entered number is Neither prime nor composite
 Entered Number is prime
Not prime
Prime number must be positive integers 

2. What is difference between == and === with an example?

Difference

• == is an comparaitive operative which compares the left anf right side value are equal.

• === is also the comparitive opeartor which strictly compares the values of each sides including it's type.

Example :

function check(){
    console.log(1==1);
    console.log("1"==1);   //Only checks values not types so return true
    console.log("1"===1);  //Check the type so returns false
}
check();

• Output:

true
true
false

Q3. How would you reverse a string in JavaScript?

Method : 1 reverse forloop method

Algorithm

• Step 1 : Start the process.

• Step 2 : initialize new String with empty velue like String2="";

• Step 3 : Iterate the given srtring in reverse manner using forloop as below:

     for (let i=String.length;i!==0;i--)
  

  • Step 3.1 : In this iteration ,conactinate the given string elements with string2 using String2 += String[i-1];

  • Step 3.2 Terminate the for loop iteration .

• Step 4 ; Print the Strings value which contains reverse value of given string

• Step 5 : Stop the process.

Program

function stringReverse(String){


let String2 = "";


for (let i=String.length;i!==0;i--){
 
  String2 += String[i-1];

}
console.log(String2);

}

stringReverse("Ajith");
stringReverse("Hi i am vijay");

• Output:

htijA
yajiv ma i iH

Method : 2 reverse string using split method

Algorithm

• Step 1 : Start the process.

• Step 2 : Split the given string into individual array elements using split method like , let split = String.split("");

• Step 3 : Reverse the string elements using reverse method , let reverse = split.reverse();

• Step 4 : Join the reversed string elements using join method , let String2 = reverse.join("");

• Step 5 : Print the final reversed string .

• Step 6 : Stop the process.

Program

function reverseString(String){

    let split = String.split("");   //It splits the string into array format "" or '' is very important

  //  console.log(split);

    let reverse = split.reverse();  // It reverse the items in array string

   // console.log(reverse);

    let String2 = reverse.join("");  //It joind the string characters of a arrat tyoe string "" or '' is very important
 
    console.log(String2);
}
reverseString("Yajiv");
reverseString("I am Vijay");

• Output:

vijaY
yajiV ma I

Q 4. How would you reverse words in a sentence?

Algorithm

• Step 1 : Start the process.

• Step 2 : Read the given sentence as string format.

• Step 3 : split the entered string using .split(" ") method , " " --> It is very important to split the sentence in space to identify words.

• Step 4 : Reverse the splited string using .reverse() method.

• Step 5 : Join the reversed string By " " with .join(" ") method to make array format to string.

• Step 6 : Store the final string.

• Step 7 : display the string.

• Step 8 : Stop the process.

Program

function reverseString(sentence){

    let split = sentence.split(" ");   //It splits the string into array format "" or '' is very important

   //console.log(split);

   let reverse = split.reverse();

   //console.log(reverse);
 
   let sentence2 = reverse.join(" ");

   console.log(sentence2);
  

   
}

reverseString("I am Vijay");
reverseString("How old are you?");

• Output:

Vijay am I
you? are old How

Q 5. How will you verify a word as a palindrome?

Palindrome :

• Palindrome menas the word that reads the same in forwars and backword.

Algorithm

• Step 1 : Start the process.

• Step 2 : Reverse the given string using for loop .

• Step 3 : Store reversed string in new variable.

• Step 4 : Compare reversed string with given string using === operaor.

  • Step 4.1 : If both are equal , Print " Palindrome "

  • Step 4.2 : If both are not equal , Print " NOT Palindrome "

• Step 5 : Stop the process.

Program

function palindromeOrNot(word){

let word2 = "";

for (let i=word.length;i!==0;i--){
    word2 += word[i-1];
}

(word2===word) ? console.log("Palindrome") : console.log("Not palindrome");

}

palindromeOrNot("vijay");
palindromeOrNot("ere");

• Output:

Not palindrome
Palindrome

Q 6. Write your own program to explain the difference between forEach and map?

• Array.foreach will not return anything but array.amp can return value.

• We can use array.filter or other other higher order functions after array.map bu we can not do that after array.forEach() method.

Program

let elements=[100,200,300,400,500];

let divide = (item) => {  return item/10 };   // Divide 10 for each element

let final = elements.map(divide);            // Using Array.map

console.log(final);                           //Array after map

console.log(elements);                       //Original array (Unchanged)


let multiply = (item) => { return (  item * 2 ) };   // forEach method will not return anything only undefined

 let mul = elements.forEach(multiply);                   

console.log(mul);            

let alter = (item) => { console.log(item * 2) }

let sec =  elements.forEach(alter);

• Output:

[ 10, 20, 30, 40, 50 ]
[ 100, 200, 300, 400, 500 ]
undefined
200
400
600
800
1000

Q 7. Generate a random number between 1 to 5?

Program

function range(min,max){
    return Math.floor(Math.random() *  (max - min + 1)) + min;
}
console.log(range(1,5));
console.log(range(1,5));
console.log(range(1,5));
console.log(range(1,5));

• Output:

4
2
4
3

Q 8. Remove duplicate from the following array?([1,2,9,4,5,8,3,5,1,4,5])

Algorithm

• Step 1 : Start the process.

• Step 2 : REad given array.

• Step 3 : Create a new empty array .

• Step 4 : Iterate over the given array usiing forloop upto the length.

• Step 5 : Check if(array2.indexOf(array1[i]) === -1),

  * Step 5.1 : If condition true , push the element in new array.
  

• Step 6 : Print the second array.

• Step 7 : Stop the process.

Program

function removeDuplicate(array1){
   
   let array2=[];
   let len = array1.length;

   for(let i=0;i<len;i++){
      if(array2.indexOf(array1[i]) === -1){
         array2.push(array1[i]);
      
      }

   }
   console.log(array2);
}
removeDuplicate([1,3,5,6,1,3,6]);
removeDuplicate([1,2,9,4,5,8,3,5,1,4,5]);

• Output:

[ 1, 3, 5, 6 ]
[
  1, 2, 9, 4,
  5, 8, 3
]

Q 9. Write a program to calculate the sum of the first 10 natural numbers.

Algorithm

• Step 1 : Start thr process.

• Step 2 : fix initial sum value to 0.

• Step 3 : Iterate with while loop untill the given number is reched.

  • Step 3.1 : set i value as 1 as natural numbers starts with 1.

  • step 3.2 : add sum and i and store it in sum.

  • Step 3.3 : Increament i for each iteration.

• Step 4 : print sum .

• Step 5 : Stop the process.

Program

function sumOfNaturalNumbers(num){
    let i=1;
let sum=0;
while(i<=num){
    sum += i;
    i++;
}
console.log(sum);
}
sumOfNaturalNumbers(10);
sumOfNaturalNumbers(2);

• Output:

55
3

Q 10. Write a program to print the sum of the even and odd numbers for a given number? (100)

Algorithm

• Step 1 : start the process.

• Step 2 : Read the number from user.

• Step 3 : initialize the oddcount=0 and evencount=0

• Step 4 : Iterate using for loop to check every numbers either odd or even upto the given number.

• Step 5 : If The number which is iterating is even , Update the value of evencount += i;

• Step 6 : Else , increase the oddcount += i;

• Step 7 : Print The Even count value and oddcount value.

• Step 8 : Stop the process.

Program

function sum(number){
    let evenCount=0;
    let oddCount=0;

    for(let i=1;i<=number;i++){
        if(i%2 === 0){
            evenCount += i;
        }
        else 
        {
             oddCount +=i;
        }
    }
    console.log("Sum Of Even Numbers :" , evenCount);
    console.log("Sum Of Odd Numbers : " , oddCount);

}
sum(100);

• Output:

Sum Of Even Numbers : 2550
Sum Of Odd Numbers :  2500

11. Write a program to merge two arrays? ([1,2,9,3,5,1,4,5], [11,54,70,40])

Algorithm

• Step 1 : Start the process.

• Step 2 : Get array1 and array 2 to merge.

• Step 3 : iterate the second array to it's length using for loop.

  • Step 3.1 : Push the each items of array2 in array1 using array.push method as follows:

    array1.push(array2[i]);

• Step 4 : Print the array1 as result.

• Step 5 : Stop the process.

Program

function mergeTwoArrays(array1,array2){

for(let i=0;i<array2.length;i++)

{
array1.push(array2[i]);
}

console.log(array1);
}
mergeTwoArrays([1,2,9,3,5,1,4,5],[11,54,70,40]);
mergeTwoArrays([1,2,3],[4,5,6]);

• Output:

[
   1,  2, 9,  3,  5,
   1,  4, 5, 11, 54,
  70, 40
]
[ 1, 2, 3, 4, 5, 6 ]

Q 12. Remove duplicate from an array of an object by id and name?

Algorithm

• Step 1 : Start the process.

• Step 2 : Read the give arrayOfObjects.

• Step 3: use array.filter method to extract the non-duplicant arrayelements.

  • Step 3.1 : Use the array.findIndex() method as inner function in the filter method to identify the repeatation of id and name of given object array.

  • Step 3.2 : check wheather t.id===thing.id && t.name===thing.name in function t.

  • Step 3.3 : Pass this function as arument to findIndex method which produces the non-duplicant array.

• Step 4 : Print the resultant array.

• Step 5 : Stop the process.

Program

function removeDuplicate(array){

    let result = array.filter((thing,index,self) => index===self.findIndex((t) => t.id===thing.id && t.name===thing.name))
    console.log(result);

}
removeDuplicate([{id: 1, name: "Stephen covey" }, {id: 2, name: "Robin Sharma" }, {id: 3, name:
    "Tolstoy"}, {id: 3, name: "Tolstoy"}, {id: 5, name: "James clear"}])

• Output:

[
  { id: 1, name: 'Stephen covey' },
  { id: 2, name: 'Robin Sharma' },
  { id: 3, name: 'Tolstoy' },
  { id: 5, name: 'James clear' }
]

Q 13. Compare two objects, If all properties are equal return true or return false?

Algorithm

• Step 1 : Start the process.

• Step 2 : Convert the objects to string form using JSON.stringify method.

• Step 3 : Assign variables for the converted objects.

• Step 4 : Compare the variables using === operator ,

  • Step 4.1 : If both are same , Print true.

  • Step 4.2 : If both are not same , print false.

• Step 5 : Stop the process.

Program

let object1 = {
    id : 1,
    name : "edison",
    age : 10
}
let object2 = {
    id : 1,
    name : "edison",
    age : 10
}
let object3 = {
    id : 1,
    name : "edison",
    age : 10
}
let object4 = {
    id : 2,
    name : "edison",
    age : 10
}
let a = JSON.stringify(object1);
let b = JSON.stringify(object2);
let c = JSON.stringify(object3);
let d = JSON.stringify(object4);

(a===b) ? console.log("True") : console.log("False");
(c===d) ? console.log("True") : console.log("False");

• Output:

True
False

Q 14. Take a multidimensional array and flat the array?[1,4,2,3,[10,20,20], [100,500,700,600],[2000,1000]]

Algorithm

• Step 1 : Start the process.

• Step 2 : Get a multidiamensional array .

• Step 3 : Usr arraynem.flat(Infinity) method to flat the array with any number of diamesndions within it.

• Step 4 : print the result.

• Step 5 : Stop the process.

Program

function arrayFlat(multi){
   console.log(multi.flat(Infinity));
}
arrayFlat([1,4,2,3,[10,20,20], [100,500,700,600],[2000,1000]]);
arrayFlat([[1,2,3,4],5,6,7]);

• Output:

[
     1,   4,   2,    3,
    10,  20,  20,  100,
   500, 700, 600, 2000,
  1000
]
[
  1, 2, 3, 4,
  5, 6, 7
]

Q 15. Group by the id of the following array of objects using the Array.reduce method?

Algorithm

• Step 1 : Start the process.

• Step 2 : Get arrayOfObjects from user.

• Step 3 : Reduce the given arrayOfObject using arrayname.reduce method as below :

  • Step 3.1 : Set An empty array as accumulator and the given arrayOfObject as current value in reduce function.

  • Step 3.2 : push the id's of the objects using array.push method in the function.

  • Step 3.3 : Return the array in the function.

• Step 4 : Print the variable which is assigned to the array.reduce method.

• Step 5 : Stop the process.

Program

function groupById(nameList){
let group_id = nameList.reduce ((arr,nameList) => {
   arr.push(nameList.id);
   return arr;
},[] )
console.log(group_id);
}
groupById([{id: 1, name: "edison" }, {id: 2, name: "Annand" }, {id: 3, name: "Vasnath"}]);

• Output:

[ 1, 2, 3 ]

Q 16. Write a program in Javascript to display the pattern like right angle triangle using an asterisk.

Sample Output

*
**
***
****
*****

Algorithm

• Step 1 : Start the process.

• Step 2 : Assign an empty string.

• Step 3 : Create an external for loop for coloumns and internal forloop for rows in pattern.

• Step 4 : Set external for loop length to given number i<=number.

• Step 5 : Set Internal forloop length as i<j .

• Step 6 : concat the * with empty string.

• Step 7 : Concat "\n" with string in external loop.

• Step 8 : Print the string.

• Step 9 : Stop the process.

Program

function pattern(number){
string="";
for(let i=1;i<=number;i++){
    
for(let j=0;j<i;j++){
    string += "*";
}
  string +="\n";
}
console.log(string);
}
pattern(5);

• Output:

*
**
***
****
*****

Q 17. Write a program in Javascript to make such a pattern like right angle triangle with number increased by 1

Sample Output:

1
2 3
4 5 6
7 8 9 10

Algorithm

• Step 1 : Start the process.

• Step 2 : Assign an empty string and temporary variable.

• Step 3 : Create an external for loop for coloumns and internal forloop for rows in pattern.

• Step 4 : Set external for loop length to given number i<=number.

• Step 5 : Set Internal forloop length as i<=j .

• Step 6 : concat the " " and the temporary variable with empty string.

  • Step 6.1 : Increament the temporary variable.

• Step 7 : Concat "\n" with string in external loop.

• Step 8 : Print the string.

• Step 9 : Stop the process.

Program

let string="";
let temp=1;
for(let i=1;i<=4;i++){
    for(let j=1;j<=i;j++){
      string += " "+temp;
      temp++;
    
    }
  string += "\n"
}
console.log(string);

• Output:

 1
 2 3
 4 5 6
 7 8 9 10

Q 18. Write a program in Javascript to make such a pattern like a pyramid with numbers increased by 1

Sample output

   1
  2 3
 4 5 6
7 8 9 10

Algorithm

• Step 1 : Start the process.

• Step 2 : Assign empty string and temporary variable.

• Step 3 : Create one outer forloop and two inner forloop.

• Step 4 : set First inner for loop to print space for every line according to the length , here 4-i.

• Step 5 : Set scond inner for loop to print the numbers and increament the temporary vriable.

• Step 6 : Set the outer forloop to make nextline in string.

• Step 7 : print the final string.

• Step 8 : Stop the process.

Program

let string="";
let temp=1;
for(let i=1;i<=4;i++){
    for(let j=1;j<=4-i;j++){
        string += " ";
    }
    for(let k=1;k<=i;k++){
      string += " "+temp;
      temp++;
    
    }
  string += "\n"
}
console.log(string);

• Output:

    1
   2 3
  4 5 6
 7 8 9 10

Q 19. Write a program in Javascript to display the pattern like a diamond

Sample output :

    *
   ***
  *****
 *******
*********
 *******
  *****
   ***
    *

Algorithm

Step 1 : Start the process.

Step 2 : Create the triangle shaped pyramid using 3 forloops with 2*(i-1) as condition in first inner forloop.

Step 3 : Created another reversed triangle using three forloop.

Step 4 : print the resultant string.

Step 5 : Stop the process.

Program

let string="";
let length=5;
for(let i=1;i<=length;i++){
    for(let j=1;j<=length-i;j++){
        string += " ";
    }
        for(let k=1;k<=2*i-1;k++){
            string += "*";
        }
        string += "\n"
    }
// Reverse method
    for(let i=1;i<=length-1;i++){
        for(let j=1;j<i+1;j++){
            string += " ";
        }
            for(let k=1;k<=2*(length-i)-1;k++){
                string += "*";
            }
            string += "\n"
        }

console.log(string);

• Output:

    *
   ***
  *****
 *******
*********
 *******
  *****
   ***
    *

Q 20. Explain following terms

a. console.log

• The log() method writes (logs) a message to the console.

• The log() method is useful for testing purposes.

Example :

console.log("hello");

• output:

hello

b. console.dir

• The method console.dir() displays an interactive list of the properties of the specified JavaScript object.

• The output is presented as a hierarchical listing with disclosure triangles that let you see the contents of child objects.

Example :

let a = {
    name : "vijay",
    age : 12
}
console.dir(a);

• Output:

{ name: 'vijay', age: 12 }

c. console.count

• The console.count() method logs the number of times that this particular call to count() has been called.

• We can give name inside the paranthesis othrwise the default will be displayed.

Example :

function show(){
    console.count("CountOfShow");
 console.log( "hi");
}
show();
show();

• Output:

CountOfShow: 1
hi
CountOfShow: 2
hi

d. console.table

• The console.table() method displays tabular data as a table.

• This function takes one mandatory argument data, which must be an array or an object, and one additional optional parameter columns.

Example :

console.table(["car","bike","lorry"]);

let object = {
    name : "vijay",
    age : 21
}
console.table(object);

function show(name , gender){
    this.name = name;
    this.gender = gender;
}

let info = new show("vijay","male");
console.table(info);

• Output:

┌─────────┬─────────┐
│ (index) │ Values  │
├─────────┼─────────┤
│    0    │  'car'  │
│    1    │ 'bike'  │
│    2    │ 'lorry' │
└─────────┴─────────┘
┌─────────┬─────────┐
│ (index) │ Values  │
├─────────┼─────────┤
│  name   │ 'vijay' │
│   age   │   21    │
└─────────┴─────────┘
┌─────────┬─────────┐
│ (index) │ Values  │
├─────────┼─────────┤
│  name   │ 'vijay' │
│ gender  │ 'male'  │
└─────────┴─────────┘

e. console.time/timeLog/timeEnd

• The time() method starts a timer in the console view.

• The time() method allows you to time code for testing purposes.

• Ue console.time() method before start of the code where you want to test and also use console.timeEnd()/console.timeLOg() after the code to see the time.

• We can use lables according to our wish.

Example :

console.time("time");
for(let i=0;i<=5;i++){
    console.log("hi");
}
console.timeEnd("time");

• Output:

hi
hi
hi
hi
hi
hi
time: 4.908ms

f. console.trace

• The trace() method displays a trace that show how the code ended up at a certain point.

• It is mainly used to trace the parents of functions.

Example :

function outer(){
    console.log("I am outer");
  
    function inner(){
        console.log("I am inner");
        console.trace();
     
    }
    inner();
}
outer();

• Output in console :

I am outer
VM35:4 I am inner
VM35:5 console.trace
inner @ VM35:5
outer @ VM35:7
(anonymous) @ VM35:9

• Output in VS code :

I am outer
I am inner
Trace
    at inner (/home/guest/Documents/JSEvaluation1/consoleStatements/trace.js:6:17)
    at outer (/home/guest/Documents/JSEvaluation1/consoleStatements/trace.js:9:5)
    at Object.<anonymous> (/home/guest/Documents/JSEvaluation1/consoleStatements/trace.js:11:1)
    at Module._compile (internal/modules/cjs/loader.js:1076:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1097:10)
    at Module.load (internal/modules/cjs/loader.js:941:32)
    at Function.Module._load (internal/modules/cjs/loader.js:782:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
    at internal/main/run_main_module.js:17:47

g. console.group/groupEnd

• The console.group() method creates a new inline group in the Web console log, causing any subsequent console messages to be indented by an additional level, until console.groupEnd() is called.

Example :

console.log("Hi");
console.group();
console.log("hello");
console.log("hello2");
console.groupEnd();

console.group("Actors");
console.log("vijay");
console.log("alith");
console.groupEnd("Actors");

• Output:

Hi
  hello
  hello2
Actors
  vijay
  alith

h. console.assert

• The assert() method writes a message to the console if an expression evaluates to false.

Example :

console.assert(1===1);   //True nothing will be return
console.assert(1+1===3);   //  Assertion failed

• Output:

Assertion failed