form.component.ts

import { PasswordValidator } from '../../validators/password.validator';
this.matching_passwords_group = new FormGroup({
	password: new FormControl('', Validators.compose([
	 	Validators.minLength(5),
	 	Validators.required,
	 	Validators.pattern('^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])[a-zA-Z0-9]+$') //this is for the letters (both uppercase and lowercase) and numbers validation
	])),
	confirm_password: new FormControl('', Validators.required)
}, (formGroup: FormGroup) => {
	 return PasswordValidator.areEqual(formGroup);
});