Test Your JavaScript Skills : ES13 (JavaScript 2022) - 37

Introduction

Namaste, In this blog I will discuss 8 code scenarios on Javascript .

1. Identify the output of the below program

    class MC {
        static mcField = "Base";    
    };
   
    class CC extends MC {
    };
   
    console.log(CC.mcField);
   

   a.error

   b.undefined

   c.null

   d.Base

   e.Child

   Answer:d

   Reason:A public static field is inherited.

2. Identify the output of the below program

    class MC {
        static mcField = "Base";
        static show() {
            console.log(MC.mcField);
        }
    };
   
    class CC extends MC {
    };
   
    CC.show();
   

   a.Child

   b.Base

   c.undefined

   d.null

   e.error

   Answer:b

   Reason:A public static method is inherited by child class.

3. Identify the output of the below program

    class MC {
        static mcField = "Base";
    };
   
    class CC extends MC {
        static show() {
            console.log(CC.mcField);
        }
    };
   
    CC.show();
   

   a.Base

   b.Child

   c.undefined

   d.null

   e.error

   Answer:a

   Reason:The public static field is inherited.

4. Identify the output of the below program

    class MyClass {
        #privateField; 
   
        constructor() {
          this.#privateField = 42; 
        }
   
        get privateValue() {
          return this.#privateField; 
        }
   
        set #privateValue(newValue) { 
          this.#privateField = newValue; 
        }
      }
   
      let instance = new MyClass();
      instance.privateValue = 100;
   

   a.error

   b.undefined

   c.null

   d.42

   e.100

   Answer:a

   Reason:A private property cannot be accessed on an object.

5. Identify the output of the below program

    let desc="Description";
   
    class Test {
        static [desc]="DB";  
    };
    console.log(Test.Description);
   

   a.Description

   b.DB

   c.error

   d.undefined

   e.null

   Answer:b

   Reason:Computed fields can be static.

6. Identify the output of the below program

    class Myclass2 {
        #i=10;
        static #j;
        show() {
         console.log(#i in this);
        }
     };
   
     let obj = new Myclass2();
     obj.show();
   

   a.10

   b.0

   c.true

   d.false

   e.error

   Answer:c

   Reason:The variable i belongs to Myclass2.

7. Identify the output of the below program

    function resolveAfter2Seconds(x) {
        return new Promise((resolve) => {
            setTimeout(() => {
                resolve(x);
            }, 1000);
        });
    }
   
    await resolveAfter2Seconds(10).then(
            arg => {console.log(arg);}
        );
   

   a.1000

   b.10

   c.error

   d.undefined

   e.null

   Answer:b

   Reason:Top level await is supported by ES13

8. Identify the output of the below program

    class Myclass2 {
        #i=10;
        static #j;
        show() {
         console.log(#j in Myclass2);
        }
     };
   
     let obj = new Myclass2();
     obj.show();
   

   a.true

   b.false

   c.undefined

   d.10

   e.error

   Answer:a

   Reason:The static variable j belongs to Myclass2.