Test Your JavaScript Skills: ES14 - 34

Introduction

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

1. Identify the output of the below program

    let arr = [11,29,7,11];
    let idx = arr.findLastIndex(arg => arg>9);
    console.log(idx);
   

   a.2

   b.1

   c.0

   d.3

   e.error

   Answer:d

   Reason:The number 11 is the last value greater than 9 which is located at index 3.

2. Identify the output of the below program

    let scores = [11, 22, 33, 41, 95];
    let arr = scores.toSpliced(0, 2); 
    console.log(arr);
   

   a.[11,22,33,41,95]

   b.[22,33,41,95]

   c.[33,41,95]

   d.[41,95]

   e.error

   Answer:c

   Reason:From index 0, 2 values are removed.

3. Identify the output of the below program

    let scores = [11, 22];
    let arr = scores.toSpliced(0, 0, 1, 2); 
    console.log(arr);
   

   a.[1,2,11,22]

   b.[2,11,22]

   c.[11,22,1,2]

   d.[11,22]

   e.error

   Answer:a

   Reason:From index 0 onwards remove 0 values and insert 1,2 values.

4. Identify the output of the below program

    let scores = [11, 22];
    let arr = scores.toSpliced(0, 2, 1, 2); 
    console.log(arr);
   

   a.[11,22]

   b.[1,2]

   c.[2,1,2]

   d.[1,2,11,22]

   e.error

   Answer:b

   Reason:From index 0 remove 2 values and insert 1,2 values.

5. Identify the output of the below program

    let ky = Symbol('mykey');
    let wkmap = new WeakMap();
    wkmap.set(ky, 'myvalue');
    console.log(wkmap.get(ky));
   

   a.myvalue

   b.error

   c.no output

   d.mykey

   e.Symbol

   Answer:a

   Reason:The output is myvalue.

6. Identify the output of the below program

    let scores = [11, 22, 33, 41, 95];
    let arr = scores.toSpliced(1, 2); 
    console.log(arr);
   

   a.[11,22,33,41,95]

   b.[11,,33,41,95]

   c.[11,22,33,41]

   d.[11,41,95]

   e.error

   Answer:d

   Reason: From index 1 onwards 2 values are removed.

7. Identify the output of the below program

    let scores = [11, 22,33];
    let arr = scores.toSpliced(1, 2, 1, 2); 
    console.log(arr);
   

   a.[11,22,33]

   b.[11,1,2]

   c.[22,1,2]

   d.[22,33,1]

   e.[1,2]

   Answer:b

   Reason:From index 1 remove 2 values and insert 1,2 values.

8. Identify the output of the below program

    let scores = [11, 22, 33, 41, 95];
    let arr = scores.toSpliced(3, 1); 
    console.log(arr);
   

   a.[11,22,33,95]

   b.[11,22,33,41]

   c.[11,22,33]

   d.[11,22,33,41,95]

   e.error

   Answer:a

   Reason:From index 3 onwards 1 value is removed.