Intro to Data Types

• Primitive types

  • undefined
  • null
  • String
  • Boolean
  • Number

• null

  • Data type
  • Value of nothing

• undefined

  • Data type
  • Absence of value, meaning nothing is assigned to a variable.

• NaN

  • Number type
  • Not a number
  • 'Hello' % 10 => NaN
    • Type coercion converts Hello to number, NaN

• Implicit type coercion

  • "3" can be converted by 3 implicitly

• Strict equality

  • === and !==
  • Check both type and value without type conversion