What are JavaScript Data Types? with code example

 


JavaScript supports several data types, which can be broadly categorized into two groups: primitive and non-primitive (also known as reference types).

  1. Primitive data types: Primitive data types are the most basic data types in JavaScript, and they are immutable (cannot be changed). There are six primitive data types in JavaScript:
  • number: represents numeric values, e.g. 1, 3.14
  • string: represents textual data, enclosed in single or double quotes, e.g. 'hello', "world"
  • boolean: represents logical values, either true or false
  • null: represents a null or empty value
  • undefined: represents a variable that has not been assigned a value
  • symbol: represents a unique identifier, introduced in ECMAScript 6

Here's an example of defining and using primitive data types in JavaScript:

javascript
let myNumber = 42; let myString = 'hello'; let myBoolean = true; let myNull = null; let myUndefined; let mySymbol = Symbol('foo'); console.log(typeof myNumber); // output: 'number' console.log(typeof myString); // output: 'string' console.log(typeof myBoolean); // output: 'boolean' console.log(typeof myNull); // output: 'object' (this is a quirk in JavaScript, typeof null returns 'object') console.log(typeof myUndefined); // output: 'undefined' console.log(typeof mySymbol); // output: 'symbol'
  1. Non-primitive data types: Non-primitive data types are reference types, which are more complex data types and can hold more complex data structures. They are mutable (can be changed). There are three non-primitive data types in JavaScript:
  • object: represents a collection of properties, e.g. {name: 'John', age: 30}
  • array: represents a collection of values, e.g. [1, 2, 3]
  • function: represents a reusable block of code that can be called, e.g. function add(a, b) { return a + b; }

Here's an example of defining and using non-primitive data types in JavaScript:

javascript
let myObject = {name: 'John', age: 30}; let myArray = [1, 2, 3]; let myFunction = function(a, b) { return a + b; }; console.log(typeof myObject); // output: 'object' console.log(typeof myArray); // output: 'object' console.log(typeof myFunction); // output: 'function'
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