Typescript regex

Question

I want to make typescript validation to this: 01-23-456789

I have one for account number :

this.contractForm.controls.account.get('accNum').setValue(val.match(/[0-9]{1,8}/g)?.join('-'))

This is easy because the account numbers look like this :

12345678-12345678-12345678

And I'm not a regex expert unfortunately, and I don't know how to make for this, that I mentioned in my first sentence.

 public businessNumberValidator() {
    return this.contractForm.controls.szerzodo
      .get('businessnum')
      .valueChanges.pipe(
        throttleTime(1),
        tap((val: string) => {
          const char = val.replace(/\D/g, '').split('');
          if (char.length > 2) {
            char.splice(2, 0, '-');
          }
          if (char.length > 5) {
            char.splice(5, 0, '-');
          }

          this.contractForm.controls.szerzodo.get('businessnum').setValue(char.join(''));
        }),
        untilDestroyed(this)
      )
      .subscribe();
  }

and I write this kind of solution, but I want a better one

i don't need the '-' , because i will join the '-', as you see in the example — Csabikaaaa
– Csabikaaaa, Commented Nov 11, 2020 at 8:54
not string number, when i start write this 4444123456, i want to autocomplete the '-', and look like this 44-44-123456 — Csabikaaaa
– Csabikaaaa, Commented Nov 11, 2020 at 8:59

Wiktor Stribiżew · Accepted Answer · 2020-11-11 11:19:28Z

2

You can use

val.replace(/\D+/g,'')
  .replace(/^(\d{1,2})(\d{1,2})?(\d{1,6})?$/, (_,x,y,z) => 
    z ? `${x}-${y}-${z}` : y ? `${x}-${y}` : x)

Here,

.replace(/\D+/g,'') - removes all non-digit chars from string
^(\d{1,2})(\d{1,2})?(\d{1,6})?$ - matches 1 or 2 first digits into Group 1 (x variable), next one or two digits are captured into an optional Group 2 (y variable), and then one to six digits are captured into an optional Group 3 (z variable); then if Group 3 matched, the replacement is Group1-Group2-Group3, if Group 2 matched, the replacement is Group1-Group2, else, the replacement is just Group 1 value.

See a JavaScript demo:

function m (val) {
  const char = val.replace(/\D/g, '').split('');
          if (char.length > 2) {
            char.splice(2, 0, '-');
          }
          if (char.length > 5) {
            char.splice(5, 0, '-');
          }
  return char.join("");
}
function m2 (val) {
  return val.replace(/\D+/g,'')
    .replace(/^(\d{1,2})(\d{1,2})?(\d{1,6})?$/, (_,x,y,z) => 
      z ? `${x}-${y}-${z}` : y ? `${x}-${y}` : x)
}
const val = "01-23-456789";

document.body.innerHTML += "<br/>=== Current approach: ===</br>"
for (let i=1; i<=val.length; i++) {
  document.body.innerHTML += m(val.substring(0,i)) + "<br/>";
}
document.body.innerHTML += "<br/>=== New regex approach: ===</br>"
for (let i=1; i<=val.length; i++) {
  document.body.innerHTML += m2(val.substring(0,i)) + "<br/>";
}

answered Nov 11, 2020 at 11:19

Wiktor Stribiżew

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1 Comment

Csabikaaaa Over a year ago

Thank you very muck dude! It worked! And also great explanation!

Alireza · Accepted Answer · 2020-11-11 08:29:09Z

-1

Use this pattern:

\d{2,6}

See Demo

answered Nov 11, 2020 at 8:29

Alireza

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