isRegExp 
Check if the given value is a regular expression.
This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to RegExp.
Signature 
typescript
function isRegExp(value: unknown): value is RegExp;Parameters 
- value(- unknown): The value to test if it is RegExp.
Returns 
(value is RegExp): True if the value is a RegExp, otherwise false.
Examples 
typescript
const value1 = /abc/;
const value2 = '/abc/';
console.log(isRegExp(value1)); // true
console.log(isRegExp(value2)); // false
