JS: Value Types
Variables don't have type.
Any value in JavaScript is one of the following type.
| type name | sample value | explanation |
|---|---|---|
| undefined † | undefined | undefined is the only value of this type.〔see undefined〕 |
| null † | null | null is the only value of this type.〔see null〕 |
| boolean † | true | true and false are the only possible values.〔see true, false〕 |
| string † | "xyz" | 〔see String Overview〕 |
| number † | 34 | Includes special value NaN (Not A Number) and Infinity〔see NaN〕 〔see Infinity〕 |
| symbol † |
Symbol()
|
Always-unique value primarily for use as property keys. 〔see Symbol Tutorial〕 |
| object | {"x":3} | The “object” type is a collection of key/value pairs. Many object has special purpsoes, e.g. Array, function, date, regex, etc. 〔see Object Type〕 |
† A value of these types are called Primitive Value.