why angular pattern regex not working in html by work well in typescript

Question

Hi, Anyone can explain to me why regex expression in pattern property is not working

  <input type="password" pattern="(?=.*[a-zA-Z])(?=.*[0-9])" minlength="6" [class.is-invalid]="passwordForm.errors && passwordForm.touched" #passwordForm="ngModel" name="password"  required class="form-control" [(ngModel)]="password">

 but i run in typescript it work well
 var mediumRegex = new RegExp("(?=.*[a-zA-Z])(?=.*[0-9])");
    console.log(
      mediumRegex.test("123asA")
  );

--->true
  console.log(
    mediumRegex.test("")
);
--->false
  console.log(
    mediumRegex.test("aaaa")
--->false

); console.log(
  mediumRegex.test("1z")
);
--->true

Please provide a minimal reproducible example of your issue. — user4676340
– user4676340, Commented Jun 5, 2019 at 8:34

Wiktor Stribiżew · Accepted Answer · 2019-06-05 08:34:51Z

1

Add a consuming .* at the end because the HTML5 regex must match and consume the whole input string (due to the fact it is wrapped with ^(?: and )$ behind the scenes when compiling the RegExp object):

<input type="password" pattern="(?=.*[a-zA-Z])(?=.*[0-9]).*" minlength="6" [class.is-invalid]="passwordForm.errors && passwordForm.touched" #passwordForm="ngModel" name="password"  required class="form-control" [(ngModel)]="password">

The pattern="(?=.*[a-zA-Z])(?=.*[0-9]).*" pattern can be improved if you replace .* in the lookaheads with reverse character classes:

pattern="(?=[^a-zA-Z]*[a-zA-Z])(?=[^0-9]*[0-9]).*"

See the principle of contrast in password regex validation.

answered Jun 5, 2019 at 8:34

Wiktor Stribiżew

631k41 gold badges502 silver badges632 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

why angular pattern regex not working in html by work well in typescript

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related