What is the purpose of the 'typeof' operator in JavaScript?
A). To check if a variable is defined
B). To check the data type of a variable
C). To assign a data type to a variable
D). To increment the value of a variable
Which statement correctly declares a JavaScript arrow function?
A). const add = (a, => a + b;
B). function add(a, { return a + b; }
C). const add = function(a, { return a + b; }
D). let add = function(a, { return a + b; };
What is the purpose of the 'continue' statement in a JavaScript loop?
A). To exit the loop
B). To skip the current iteration
C). To restart the loop
D). To execute the loop body again
What is the purpose of the 'constructor' method in a JavaScript class?
A). To create new instances of the class
B). To initialize class properties
C). To define class methods
D). To define class inheritance
How can you prevent a JavaScript function from executing immediately?
A). Using async/await
B). Using the defer attribute in HTML script tag
C). Wrapping the function in parentheses
D). Using the setTimeout function
What is the correct way to declare a variable in JavaScript?
A). var x = 10;
B). let x = 10;
C). const x = 10;
D). variable x = 10;
How do you access the last element of a JavaScript array?
A). colors[colors.length - 1];
B). colors.last();
C). colors[-1];
D). colors.getLast();
What is the purpose of the 'return' statement in a JavaScript function?
A). To end the function execution
B). To return a value from the function
C). To print a value to the console
D). To declare a variable
Which statement correctly declares a JavaScript object?
A). let person = {name: 'John', age: 30};
B). const person = ('name' => 'John', 'age' => 30);
C). const person = ['name', 'John', 'age', 30];
D). var person = {name: 'John', age: 30};
What does the '===' operator check in JavaScript?
A). Type and value equality
B). Type equality only
C). Value equality only
D). Reference equality