What will be the output of the following JavaScript code?
int sum=0;
var arr = [10,15,20,30];
arr.forEach(function myFunction(element)
{
sum= sum+element;
});
document.writeln(sum);
var arr = [10,15,20,30];
arr.forEach(function myFunction(element)
{
sum= sum+element;
});
document.writeln(sum);
70
75
10
error
Correct Answer :
B. 75
Explanation: forEach is a predefined function in Javascript which used to traverse through the array. It works in a similar way to for loop and iterates through each value in array.
Related Questions
What will be the output of the following Javascript code?
var txt1 = good;
var txt2 = day;
document.getElementById(demo).innerHTML = txt1 + txt2;
var txt2 = day;
document.getElementById(demo).innerHTML = txt1 + txt2;
good day
goodday
error
undefined
What will be the output of the following JavaScript code?
7.25
-7.25
7
-7
The property of a primary expression is ____________
stand-alone expressions
basic expressions containing all necessary functions
contains variable references alone
contains only keywords
What will be the output of the following JavaScript code?
string a = hi;
string b =there;
alert(a+b);
string b =there;
alert(a+b);
hi
there
hithere
undefined
What will be the output of the following JavaScript code?
const obj1 = { property1: '10'};
const obj2 = Object.freeze(obj1);
obj2.property1 = '20';
console.log(obj2.property1);
const obj2 = Object.freeze(obj1);
obj2.property1 = '20';
console.log(obj2.property1);
10
20
Runtime error
Compilation error
What will happen if a return statement does not have an associated expression?
It returns the value 0
It will throw an exception
It returns the undefined value
It will throw an error
Consider the following code snippet :
function constfuncs()
{
var funcs = [];
for(var i = 0; i < 10; i++)
funcs[i] = function() { return i; };
return funcs;
}
var funcs = constfuncs();
funcs[5]()
What does the last statement return ?
{
var funcs = [];
for(var i = 0; i < 10; i++)
funcs[i] = function() { return i; };
return funcs;
}
var funcs = constfuncs();
funcs[5]()
9
0
10
None of the mentioned
What is the prototype represents in the following JavaScript code snippet?
function f() {};
Function f
A custom constructor
Prototype of a function
Not valid
The main purpose of a Live Wire in NetScape is to ________
Create linkage between client side and server side
Permit server side, JavaScript code, to connect to RDBMS
Support only non relational database
To interpret JavaScript code
The function stops its execution when it encounters?
continue statement
break statement
goto statement
return statement
What kind of expression is new Point(2,3)?
Primary Expression
Object Creation Expression
Invocation Expression
Constructor Calling Expression
What is a block statement in JavaScript?
conditional block
block that contains a single statement
both conditional block and a single statement
block that combines multiple statements into a single compound statement
The unordered collection of properties, each of which has a name and a value is called _________
String
Object
Serialized Object
Array
What is the observation made in the following JavaScript code?
if (!a[i]) continue;
Skips the defined elements
Skips the existent elements
Skips the null elements
Skips the defined & existent elements
What will be the output of the following JavaScript code?
function compare()
{
int a=1;
char b=1;
if(a.tostring()===b)
return true;
else
return false;
}
{
int a=1;
char b=1;
if(a.tostring()===b)
return true;
else
return false;
}
true
false
runtime error
logical error
When an empty statement is encountered, a JavaScript interpreter __________
Ignores the statement
Prompts to complete the statement
Throws an error
Shows a warning
What will be the output of the following JavaScript code?
const object1 = {};
a = Symbol('a');
b = Symbol.for('b');
object1[a] = 'harry';
object1[b] = 'derry';
const objectSymbols = Object.getOwnPropertySymbols(object1);
console.log(objectSymbols.length);
a = Symbol('a');
b = Symbol.for('b');
object1[a] = 'harry';
object1[b] = 'derry';
const objectSymbols = Object.getOwnPropertySymbols(object1);
console.log(objectSymbols.length);
0
2
1
Error
To determine whether one object is the prototype of (or is part of the prototype chain of) another object, one should use the ____________
isPrototypeOf() method
equals() method
=== operator
==opertor
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
Stores the elements of an array in normal order
Consider the following code snippet.
function printArray(a)
{
var len = a.length, i = 0;
if (len == 0)
console.log(Empty Array);
else
{
do
{
console.log(a[i]);
} while (++i < len);
}
}
What does the above code result?
{
var len = a.length, i = 0;
if (len == 0)
console.log(Empty Array);
else
{
do
{
console.log(a[i]);
} while (++i < len);
}
}
Prints the numbers in the array in order
Prints the numbers in the array in the reverse order
Prints 0 to the length of the array
Prints Empty Array
What will be the output of the following JavaScript code?
var grade='B';
var result;
switch(grade)
{
case 'A':
{
result+=10;
break;
}
case 'B':
{
result+= 9;
break;
}
case 'C':
{
result+= 8;
break;
}
default:
result+= 0;
}
document.write(result);
var result;
switch(grade)
{
case 'A':
{
result+=10;
break;
}
case 'B':
{
result+= 9;
break;
}
case 'C':
{
result+= 8;
break;
}
default:
result+= 0;
}
document.write(result);
10
9
8
0
What is the observation made in the following JavaScript code?
var count = [1,,3];
The omitted value takes undefined
This results in an error
This results in an exception
The omitted value takes an integer value
The one-liner code that concatenates all strings passed into a function is
function concatenate()
{
return String.prototype.concat('', arguments);
}
function concatenate()
{
return String.prototype.apply('', arguments);
}
function concatenate()
{
return String.concat.apply('', arguments);
}
function concatenate()
{
return String.prototype.concat.apply('', arguments);
}
What will be the output of the following JavaScript code?
function equalto()
{
int num=10;
if(num===10)
return true;
else
return false;
}
{
int num=10;
if(num===10)
return true;
else
return false;
}
true
false
runtime error
compilation error
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
pass the elements of the array into another array
The type of a variable that is volatile is _______________
Volatile variable
Mutable variable
Immutable variable
Dynamic variable
What will be the output of the following Javascript code?
<script>
var x = 10;
x *= 5;
document.getElementById("demo").innerHTML = x;
</script>
var x = 10;
x *= 5;
document.getElementById("demo").innerHTML = x;
</script>
5
10
50
Error
Consider the following code snippet.
for(var p in o)
console.log(o[p]);
The above code is equivalent to which code?
console.log(o[p]);
for (var i = 0;i < a.length;i++)
console.log(a[i]);
for (int i = 0;i < a.length;i++)
console.log(a[i]);
for (var i = 0;i <= a.length;i++)
console.log(a[i]);
for (var i = 1;i < a.length;i++)
console.log(a[i]);
The method or operator used to identify the array is __________
isarrayType()
==
===
typeof
Consider the following code snippet
function f(o)
{
if (o === undefined) debugger;
}
What could be the task of the statement debugger?
{
if (o === undefined) debugger;
}
It does nothing but a simple breakpoint
It debugs the error in that statement and restarts the statements execution
It is used as a keyword that debugs the entire program at once
It is used to find error in the statement