Regex form validator passes when given no input


I want to assert that my form field input is an integer greater than or equal to one. My validation function is: Validators.pattern('^[1-9]+\d*$') - this works if there is anything at all entered into the ion-input but falsely reports that the form is valid if nothing at all is entered. I can combine my validator with Validators.required but I wanted to check if this is considered correct behaviour? Is there a better way to do what I’m trying to do?