Array And Function(Computer Science > Javascript ) Questions and Answers
Question 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
Explanation:-
Answer: Option A. -> The omitted value takes “undefined”
Question 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
Explanation:-
Answer: Option A. -> true false
Question 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
Explanation:-
Answer: Option A. -> decrements the total length by 1
Question 4. 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
Explanation:-
Answer: Option A. -> Reverses and stores in the same array
Question 5. 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
Explanation:-
Answer: Option D. -> All of the mentioned
Question 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]
Explanation:-
Answer: Option A. -> Returns [1,2,3]
Question 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
Explanation:-
Answer: Option A. -> 1
Question 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
Explanation:-
Answer: Option C. -> 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
Question 9. The method or operator used to identify the array is
isarrayType()
==
===
typeof
Explanation:-
Answer: Option D. -> typeof
Question 10. The reduce and reduceRight methods follow a common operation called
