Type Alias Primitive<T>

Primitive type of JSON.

Primitive<T> is a TMP (Type Meta Programming) type which converts its argument as a primitive type within framework JSON.

If the target argument is a built-in class which returns its origin primitive type through the valueOf() method like the String or Number, its return type would be the string or number. Otherwise, the built-in class does not have the valueOf() method, the return type would be an empty object ({}).

Otherwise, the target argument is a type of custom class, all of its custom method would be erased and its prototype would be changed to the primitive object. Therefore, return type of the TMP type finally be the primitive object.

In addition, if the target argument is a type of custom class and it has a special method toJSON(), return type of this Primitive would be not Primitive<Instance> but Primitive<ReturnType<Instance.toJSON>>.

Before	After
Boolean	boolean
Number	number
String	string
Class	object
Class with toJSON()	Primitive<ReturnType<Class.toJSON>>
Native Class	never
Others	No change