JavaScript Data Types
Table of Contents
JavaScript has 8 data types:
- Undefined (
undefined
) - Null (
null
) - Boolean (
true
/false
) - Number
- BigInt
- String
- Symbol (unique value)
- Object
Object is the only mutable type. Other types are immutable and are called primitive types.
Undefined #
The Undefined type has only one value: undefined
, which means a variable is declared but no value is assigned to it.
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undefined
can be assigned to a variable but one should use null
to represent emptiness.
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Null #
The Null type has only one value: null
, which means empty.
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Boolean #
The Boolean type has two values: true
and false
. The Boolean values are usually used in conditional operations.
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Number #
The Number type represents both integer and floating point numbers.
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The Number type contains some special values: Infinity
, -Infinity
and NaN
(Not a Number).
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JavaScript can only safely store integers in the range of Number.MIN_SAFE_INTEGER
-(253 β 1) to Number.MAX_SAFE_INTEGER
(253 β 1).
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BigInt #
The BigInt type can safely store integers beyond Number.MIN_SAFE_INTEGER
and Number.MAX_SAFE_INTEGER
. To create a BigInt value, append n
to an integer or call the BigInt()
function. Note that when BigInt()
accept a number beyond the safe limits, the number will be rounded.
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String #
The String type represents text.
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Symbol #
The Symbol type represents a unique and immutable value. To create a Symbol value, call Symbol()
function with an optional string as its description.
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Object #
Object is a collection of key-value pairs, similar to a dictionary.
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References #
- Data types - javascript.info
- JavaScript data types and data structures - JavaScript | MDN
- What is the difference between null and undefined in JavaScript? - Stack Overflow#57249968