I would recommend using the execute method which returns null if no match exists otherwise it returns a helpful object.
let case1 = /^([a-z0-9]{5,})$/.exec("abc1");
console.log(case1); //null
let case2 = /^([a-z0-9]{5,})$/.exec("pass3434");
console.log(case2); // ['pass3434', 'pass3434', index:0, input:'pass3434', groups: undefined]