Detects whether the passed value is exclusively the only available function type of ES3 (in addition to all the built-in constructors).
value
Optional
An optionally passed value of any type.
A boolean value which indicates whether the tested value is exclusively the only available/known function type back at ES3 (in addition to all the built-in constructor functions).
Detects whether the passed
valueis exclusively the only available function type of ES3 (in addition to all the built-in constructors).