Function isA

isA<T extends new (...args: any) => any>(
x: unknown,
classConstructor: T,
): x is InstanceType<T>
Checks if a provided value is an instance of the provided class

This does not throw for some cases where JavaScript chokes ()
Type Parameters
- T extends new (...args: any) => any
Parameters
- x: unknown
  possibly an instance of a class
- classConstructor: T
  a class constructor (usually starts with big letter!)
Returns x is InstanceType<T>
Example
```
isA({}, Object) => true
isA(Promise.resolve, Promise) => true
isA(/hello/i, RegExp) => true
isA('plain str', String) => false
isA(new String('str obj'), String) => true
isA(22, Number) => false
isA(new Number(33), Number) => true
isA(2, NaN) => false // Note that `2 instanceof NaN` throws
```
Throws
if classConstructor is not a function.
- Defined in object.ts:55