includes
includes() function
Checks if the specified value is equal.
There is another alias function called contains.
Signature:
declare function includes<T extends readonly []>(value: unknown, iterable: T): false;
Example
includes('c', 'abcd'); // true
includes('e', 'abcd'); // false
includes(3, [1,2,3,4]); // true
includes(5, [1,2,3,4]); // false