Basic JavaScript

Question 1

What are the immutable data types in javascript?

Answer 1

Boolean, Null, Undefined, Number, String, and Symbol

tip: use the acronym BUNS²

Question 2

And the mutable data types ?

Answer 2

Array and Objects

Question 3

What are six false values in Javascript Boolean Function ?

Answer 3

Undefined, Null, 0 (Zero), false, “” or ‘’ (Empty) and NaN

tip: use the acronym Um Zero em falso não é nulo.

Question 4

How to define comments in your code so that interpreter of Javascript display it at called of a function ?
Show an example.

Answer 4

This syntax makes the interpreter of Javascript display the comment in the format of documentation. Try it!

/**
 * A long process to prepare tea.
 * @return {string} A cup of tea.
 **/
const prepareTea = () => 'greenTea';