Test Your JavaScript Skills : ES13 (JavaScript 2022) - 35

Introduction

Namaste, In this blog I will discuss 10 code scenarios on Javascript .

1. Identify the output of the below program

    let arr=[1,2,3,4,5];
    console.log(arr.at(-1));
   

   a.4

   b.1

   c.2

   d.5

   e.error

   Answer:d

   Reason:The value at index -1 is 5.

2. Identify the output of the below program

    let emp = {
        no:100,
        name:"ram",
        salary:1000
    };
   
    console.log(Object.hasOwn(emp,'no'));
   

   a.true

   b.false

   c.error

   d.100

   e.ram

   Answer:a

   Reason:The 'no' property belongs to emp object.

3. Identify the output of the below program

    function connectToDatabase(usn,pwd) {
        let connectionError = new Error("Invalid USN/PWD");
        let str = 'usn:' + usn +' pwd:' + pwd;
        connectionError.cause = new Error(str);
        throw connectionError;
    }
   
    function getDataFromDatabase() {
        try {
            connectToDatabase("ram","javascript");        
        }catch (error) {
            if (error.cause) {
                console.log(error.cause);
            }
        }
    }
   
    getDataFromDatabase();
   

   a.no output

   b.Invalid USN/PWD

   c.db Connect

   d.Error: usn:ram pwd:javascript

   e.error

   Answer:d

   Reason:By computation the result is Error: usn:ram pwd:javascript.

4. Identify the output of the below program

    class Emp {
        eno=100;
        ename="ram";
        constructor() {
        }
    };
   
    let obj = new Emp();
    console.log(obj.eno,obj.ename);
   

   a.100 ram

   b.undefined undefined

   c.ram

   d.error

   e.object object

   Answer: a

   Reason:The class variables can be initialized and accessed.

5. Identify the output of the below program

    class Emp {
        #eno=100;
        ename="ram";
        #constructor() {
        }
   
    };
   
    let obj = new Emp();
    console.log(obj.ename);
   

   a.error

   b.100

   c.ram

   d.undefined

   e.null

   Answer:a

   Reason:Constructor cannot be private.

6. Identify the output of the below program

    let arr=[1,2,3,4,5];
    console.log(arr.at(3));
   

   a.1

   b.2

   c.3

   d.4

   e.5

   Answer:d

   Reason: The value at index 3 is 4.

7. Identify the output of the below program

    class Emp {
        #eno=100;
        ename="ram";
        constructor() {
        }
    };
   
    let obj = new Emp();
    console.log(obj.eno);
   

   a.error

   b.100

   c.undefined

   d.null

   e.ram

   Answer:c

   Reason:The private members cannot be accessed on object.

8. Identify the output of the below program

   
    let emp = {
        no:100,
        name:"ram",
        salary:1000
    };
   
    console.log(Object.hasOwn(emp,'dept'));
   

   a.error

   b.ram

   c.1000

   d.false

   e.true

   Answer:d

   Reason:The property 'dept' does not exists on emp object.

9. Identify the output of the below program

    class Emp {
        #eno=100;
        ename="ram";
        constructor() {
        }
        #fx() {
            console.log(this.#eno);
        }
    };
   
    let obj = new Emp();
    obj.fx();
   

   a.100

   b.undefined

   c.null

   d.error

   e.ram

   Answer:d

   Reason: Private function when accessed on object yields into error.

10. Identify the output of the below program

    let arr=[1,2,3,4,5];
    console.log(arr.at(-5));
    

    a.5

    b.4

    c.3

    d.2

    e.1

    Answer:e

    Reason:The value at index -5 is 1 .