Time validator in Angular and Javascript

We want to validate an input, the required format is hh:mm

Examples:

8:59 AM = 08:59

8:59 PM = 20:59

Javascript regular expression

/^(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$/

Angular form

formControl = new FormControl('',
 Validators.pattern(/^(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$/));

Notice that we are not using a string but a JS/TS RegExp