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Javascript Array MCQ Questions and Answers

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Javascript Array MCQ Questions and Answers : We provide quiz questions on Javascript Array where you can learn lots of objective questions with answers and you can also download pdf of javascript.

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1) Consider the code snippet given below

var count = [1,,3];

What is the observation made?

    The omitted value takes “undefined”
    This results in an error
    This results in an exception
    None of the mentioned

Answer : A Discuss

2) Consider the following code snippet

  var a1 = [,,,];
  var a2 = new Array(3);
  0 in a1
  0 in a2
The result would be

    true false
    false true
    true true
    false true

Answer : A Discuss

3) The pop() method of the array does which of the following task ?

    decrements the total length by 1
    increments the total length by 1
    prints the first element but no effect on the length
    None of the mentioned

Answer : A Discuss

4) Consider the following code snippet :

 if (!a[i]) continue;

What is the observation made ?

    Skips the undefined elements
    Skips the non existent elements
    Skips the null elements
    All of the mentioned

Answer : D Discuss

5) What will happen if reverse() and join() methods are used simultaneously ?

    Reverses and stores in the same array
    Reverses and concatenates the elements of the array
    Reverses
    All of the mentioned

Answer : A Discuss

6) Consider the following code snippet :

var a = [1,2,3,4,5];
 a.slice(0,3);

What is the possible output for the above code snippet ?

    Returns [1,2,3].
    Returns [4,5].
    Returns [1,2,3,4].
    Returns [1,2,3,4,5].

Answer : A Discuss

7) Consider the following code snippet :

  var a = [];
  a.unshift(1);
  a.unshift(22);
  a.shift();
  a.unshift(3,[4,5]);
  a.shift();
  a.shift();
 a.shift();

The final output for the shift() is

    1
    [4,5].
    [3,4,5].
    Exception is thrown

Answer : A Discuss

8) The primary purpose of the array map() function is that it

    maps the elements of another array into itself
    passes each element of the array and returns the necessary mapped elements
    passes each element of the array on which it is invoked to the function you specify, and returns an array containing the values returned by that function
    None of the mentioned

Answer : C Discuss

9) The reduce and reduceRight methods follow a common operation called

    filter and fold
    inject and fold
    finger and fold
    fold

Answer : B Discuss

10) The method or operator used to identify the array is

    isarrayType()
    ==
    ===
    typeof

Answer : D Discuss

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