Data Types:

• number
  • Infinity
  • NaN
• string
• boolean
• null
• undefined
• object
  • Array
• function

Para saber o tipo da variavel

typeof "aawdaw"
'string'
typeof NaN
'number'
typeof null
'object'

Colocar o valor null dentro da variável muda o tipo dela

Data and Structure types

The latest ECMAScript standard defines nine types:

• Six Data Types that are primitives, checked by typeof operator:
  • undefined : typeof instance === "undefined"
  • Boolean : typeof instance === "boolean"
  • Number : typeof instance === "number"
  • String : typeof instance === "string"
  • BigInt : typeof instance === "bigint"
  • Symbol : typeof instance === "symbol"
• Structural Types:
  • Object : typeof instance === "object". Special non-data but Structural type for any constructed object instance also used as data structures: new Object, new Array, new Map, new Set, new WeakMap, new WeakSet, new Date and almost everything made with new keyword;
  • Function : a non-data structure, though it also answers for typeof operator: typeof instance === "function". This is merely a special shorthand for Functions, though every Function constructor is derived from Object constructor.
• Structural Root Primitive:
  • null : typeof instance === "object". Special primitive type having additional usage for its value: if object is not inherited, then null is shown;