Types of data
JavaScript has the following types of data that can store values. We will consider three in this module and the other two later.
| Covered here | Covered later |
|---|---|
| numbers | objects |
| strings | functions |
| Booleans |
In addition, there are the following built-in values:
| Value | Data type |
|---|---|
null |
object |
undefined |
undefined |
To determine the type of a value, you can use the built-in function typeof. Notice that whether or not they use decimal points, all numbers are of type number. Notice also that the value undefined is of type undefined, and that (due to a quirk in JavaScript) the value of null is of type object.
You can tell by both the colour of the values in the console and the quotation marks that typeof returns a string.
Note:
Hints:
- undefined
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
1
2
console.log(typeof(5));
console.log(typeof(5.0));
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX