Types

• Has 7 different types in Javascript
• number
• boolean
• string
• undefined
• null (primitive)
• Symbol()
• object
• undefined vs null
• undefined is the absence of definition
  • In object hoisting we use undefined
• null is absence of value
• Types are categorized in 2 sections
• Primitive (Represents single value)
  • number
  • boolean
  • string
  • undefined
  • null (primitive)
  • Symbol()
• Non-Primitive
  • object
  • array
  • function

• Array type

• typoOf [] returns object

• In JS the array is interpreted as below

js var myArr = ['a', 'b', 'c'];

This is same as below syntax.

js var myArr = { 0: 'a', 1: 'b', 2: 'c' };

• Since both object and array is type of object, we can determine an array by using the Array object and its isArray() method.

js console.log(Array.isArray([1, 2, 3])); console.log(Array.isArray({}));

Here the first one will print true and the second one false.