Type is a characteristic of avalue affecting what kind of data it can store, and the structure that the data will adhere to. For example, abooleanData Type can hold only atrue orfalse value at any given time, whereas astring has the ability to hold a string or a sequence of characters, anumber can hold numerical values of any kind, and so on.

A value's data type also affects the operations that are valid on that value. For example, a value of type number can be multiplied by another number, but not by a string - even if that string containsonly a number, such as the string "2".

Types also provides us with useful knowledge about the comparison between different values. Comparison between structured types is not always an easy assumption, as even if the previous data structure is the same, there could be inherited structures inside of thePrototype Chain.

If you are unsure of the type of a value, you can use thetypeof operator.

See also

• Data type on Wikipedia
• JavaScript data types
• Related glossary terms:
  • JavaScript
  • string
  • number
  • bigint
  • boolean
  • null
  • undefined
  • symbol