Check at least 4 different character in password-CodePudding

I need regex that check if a String (password) contains: letters, numbers, at least 6 character (length) AND (this going the problem) at least 4 different characters.

(Password can contains only letters or only numbers but at least 4 different char.)

So far i have been using this but this can not check at least 4 different characters

/^\S(?=.*[A-Za-z])(?=.*\d)[A-Za-z\d]{6,}$/i

Thx if u have any Idea

CodePudding user response：

Assuming the string can contain only letters and numbers, an example of a JavaScript regex that fulfills your requirements is:

const regex = /^(?=.*(.).*(?!\1)(.).*(?!\1|\2)(.).*(?!\1|\2|\3).)[a-z\d]{6,}$/i;

console.log(regex.test('abc'));       // false
console.log(regex.test('abcbaa'));    // false

console.log(regex.test('abcdaa'));    // true

CodePudding user response：

If you don't mind an extra check to make the at least 4 different characters part a bit more flexible, you can use your pattern in combination with a Set.

const regex = /^(?=[^a-z\n]*[a-z])(?=[^\d\n]*\d)[a-z\d]{6,}$/i;
const check = (s) => regex.test(s) && (new Set(s)).size > 3;
[
  "abc5",
  "abcdef",
  "123456",
  "aaaaa1",
  "aaaa12",
  "abcbaa",
  "abcdaa",
  "aaa123",
  "abc1aa",
  "1112ab"

].forEach(s =>
  console.log(`${s} --> ${check(s) ? "Match" : "No match"}`)
)