Concepts

Question 1

What is assign by value vs reference

Answer 1

when assigning to a value it can be reassigned however by reference with arrays and objects is simply pointing to a number entry in the stack so you cannot overwrite without using certain methods

Question 2

What is a Higher order component

Answer 2

It is a function that takes in a component and returns a component

Question 3

What is callback hell

Answer 3

Callback hell refers to the situation where callbacks are nested within other callbacks several levels deep, potentially making it difficult to understand and maintain the code.

Question 4

What is a tick function

Answer 4

It returns a promise that resolves as soon as any pending state changes have been applied to the DOM (or immediately, if there are no pending state changes).

Question 5

What is the difference between a pure component and a functional component

Answer 5

In a functional component you can use state hooks to pass around data whereas in class you need to use props. In a functional component you can use useEffect for mounting versus having to use multiple mount functions like in class components.

Question 6

What is recursion

Answer 6

Recursion is when a function calls itself until someone stops it. It can be used instead of a loop. If no one stops it, it’ll recurse forever and crash your program. A base case is a condition that stops the recursion.

Question 7

What is closure

Answer 7

A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment). In other words, a closure gives you access to an outer function’s scope from an inner function.
Closure helps if you want to hide a variable value inside a function and be able to not have to worry about it getting changed globally.