Test Your JavaScript Skills: ES14 - 33

Introduction

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

1. Identify the output of the below program

    let arr = [,,"ram",10];
    let arr2 = arr.toSorted();
    console.log(arr2);
   

   a.error

   b.[undefined, undefined,10,'ram']

   c.[10, 'ram', undefined, undefined]

   d.[10,'ram']

   e.[10,'ram', null, null]

   Answer:c

   Reason:Empty values are converted to undefined.

2. Identify the output of the below program

    let arr = [100,21,13];
    let arr2 = arr.toSorted(); 
    console.log(arr2);
   

   a.[100,21,13]

   b.[100,13,21]

   c.[13,21,100]

   d.[21,13,100]

   e.error

   Answer:b

   Reason:The elements are converted to string then sorted based on ASCII values.

3. Identify the output of the below program

    let arr = [100,21,13];
    let arr2 = arr.toReversed();
    console.log(arr2);
   

   a.[100,21,13]

   b.[13,100,21]

   c.[13,21,100]

   d.[100,13,21]

   e.error

   Answer:c

   Reason:A new reversed array is created.

4. Identify the output of the below program

   
    let arr = [100,21,13];
    let arr2 = arr.with(2,999);
    console.log(arr2);
   

   a.999

   b.13

   c.[100,21,999]

   d.error

   e.[100,13,999]

   Answer:c

   Reason:Returns a changed updated array

5. Identify the output of the below program

    let arr = [11,29,63,90,29,74];
    let v = arr.findLast(arg => arg > 20);
    console.log(v);
   

   a.29

   b.63

   c.90

   d.74

   e.error

   Answer:d

   Reason:The last value greater than 20 is 74

6. Identify the output of the below program

    let nums = [9,8,5,2,4,1,3,4,5];
    let a = nums.findLast(arg => { 
        if (arg==5 || arg == 8)
            return arg;
    });
    console.log(a);
   

   a.5

   b.8

   c.9

   d.2

   e.error

   Answer:a

   Reason:The last matching value is 5.

7. Identify the output of the below program

   
    let arr = [100,21,13];
    let arr2 = arr.toReversed();
    console.log(arr);
   

   a.[100,21,13]

   b.[13,21,100]

   c.[21,13,100]

   d.[100,13,21]

   e.error

   Answer: a

   Reason: The host array is not reversed.

8. Identify the output of the below program

    let arr = [11,29,63,90,29,74];
    let v = arr.findLast(arg => arg < 34);
    console.log("last value", v);
   

   a.11

   b.29

   c.63

   d.error

   e.no output

   Answer:b

   Reason:The last value less than 34 is 29.

9. Identify the output of the below program

    let arr = [1, 2, 3];
    let arr2 = arr.with(0, 6); 
    console.log(arr2);
   

   a.6

   b.[0,2,3]

   c.[1,2,6]

   d.[6,2,3]

   e.error

   Answer:d

   Reason:The with() function returns the updated array.

10. Identify the output of the below program

    let users = [
        { id: 1, name: 'Blic' },
        { id: 2, name: 'Balram' },
        { id: 3, name: 'Baldev' },
      ];
      let lastUser = users.findLast((user) => user.name.startsWith('B'));
      console.log(lastUser.name);
    

    a.Blic

    b.Balram

    c.Baldev

    d.error

    e.undefined

    Answer:c

    Reason:The last matching value is Baldev