Basics

Question 1

What are static methods?

Answer 1

Methods that belong to a class instead of an instance. They’re called on the class itself. They don’t have access to the this object, which is the instance-specific data. They’re defined with the “static” keyword.

Question 2

What are instance methods?

Answer 2

Methods that belong to a class instance. They have access to the this object. They don’t need any keyword to be defined.

Question 3

What is IIFE?

Answer 3

Immediately Invoked Function Expression.

Question 4

What is a callback?

Answer 4

A function that is passed into another function as an argument, which is then invoked inside the outer function to complete a task or routine.

Question 5

What is === and == ?

Answer 5

Strict equality and loose equality. Double equals perform type conversion before comparing, triple equals doesn’t.

Question 6

What are primitives?

Answer 6

A primitive is a data type that is not an object and does not contain methods or properties.

Question 7

What are the 7 primitives of JavaScript?

Answer 7

1. null
2. undefined
3. number
4. bigint
5. string
6. boolean
7. symbol

Question 8

What’s the difference between Primitive types and Reference types?

Answer 8

Primitive type values get stored directly in the stack (when declared at the top level) and Reference type values are stored in the heap with a reference in the stack.

Question 9

What is a data type?

Answer 9

It’s a blueprint of how data is represented in the computer’s memory.

Programming languages manipulate values, those values belong to a type. Variables can hold values, a data type defines the kind of value the variable can hold.