Answer: A
JavaScript only has primitive types and objects.
Primitive types are boolean
, null
, undefined
, bigint
, number
, string
, and symbol
.
What differentiates a primitive from an object is that primitives do not have any properties or methods; however, you'll note that 'foo'.toUpperCase()
evaluates to 'FOO'
and does not result in a TypeError
. This is because when you try to access a property or method on a primitive like a string, JavaScript will implicitly wrap the primitive type using one of the wrapper classes, i.e. String
, and then immediately discard the wrapper after the expression evaluates. All primitives except for null
and undefined
exhibit this behaviour.