Q
What will be the output of the following code? var double = function(x) { return x * 2; }; console.log(double(5));

Answer & Solution

Answer: Option A
Solution:
The function double returns x * 2, so console.log(double(5)) outputs 10.
Related Questions on Average

What will be the output of the following code? var multiply = (x, y) => x * y; console.log(multiply(3, 4));

A). 12

B). 34

C). multiply

D). undefined

Which of the following is true about functions in JavaScript?

A). Functions can be assigned to variables

B). Functions can be passed as arguments to other functions

C). Functions can be returned from other functions

D). All of the above

How do you assign a function to a variable in JavaScript?

A). var greet = function() { alert('Hello'); };

B). var greet = function { alert('Hello'); };

C). function greet() { alert('Hello'); }

D). var greet = function alert('Hello');

How can you invoke a function stored in a variable doSomething?

A). doSomething();

B). call doSomething;

C). doSomething[];

D). invoke(doSomething);

How can you store a function as a property of an object?

A). var obj = { method: function() { alert('Hello'); } };

B). var obj = { method: alert('Hello'); };

C). var obj = { method: function { alert('Hello'); } };

D). var obj = { function() { alert('Hello'); } };

What will be the output of the following code? var add = new Function('a', 'b', 'return a + b'); console.log(add(2, 3));

A). 5

B). add

C). undefined

D). 2 3

How do you create an Immediately Invoked Function Expression (IIFE)?

A). (function() { alert('IIFE'); })();

B). function() { alert('IIFE'); }();

C). (function { alert('IIFE'); })();

D). function() { alert('IIFE'); };

What will be the output of the following code? var counter = (function() { var count = 0; return function() { return ++count; }; })(); console.log(counter()); console.log(counter());

A). 1, 2

B). 0, 1

C). undefined, undefined

D). 2, 4

How do you define an anonymous function assigned to a variable?

A). var anon = function() { alert('Anonymous!'); };

B). var anon = function { alert('Anonymous!'); };

C). function anon() { alert('Anonymous!'); }

D). var anon = function anonymous() { alert('Anonymous!'); };

How do you define a function using a function expression?

A). var myFunc = function() { alert('Hello'); };

B). function myFunc() { alert('Hello'); }

C). var myFunc = function { alert('Hello'); };

D). var myFunc() { alert('Hello'); }