CODEWITHSUNDEEP
javascriptregex
Gergő Horváth
Gergő Horváth

Reputation: 3705

How to define different regex for the first character, and the rest of the string?

I want to validate and process a string, which should be a telephone number. For the first character, numbers and + is accepted, for the rest, just numbers.

I have the solution to accept + and numbers, but just for the whole string: 

console.log("asd242++asf43+234".replace(/[^+\d]/g, ""))

But suffering from defining different check for the first character, and the rest.

Upvotes: 0

Views: 1434

Answers (3)

bkis
bkis

Reputation: 2587

You can use the following:

([^+\d]|(?!^)\+)

It matches everything that is not a digit nor a + and doesn't match + at the beginning of the string!
So your test log would look like this:

console.log("+asd242++asf43+234".replace(/([^+\d]|(?!^)\+)/g, ""))

(i added a + to the beginning to show it handles this correctly!)

See a Demo that shows it matches all your cases!

Upvotes: 1

kszdev
kszdev

Reputation: 31

Try this one: /^[+]?[0-9]+$/g

^ - start of string

[+]? - single optional + character

[0-9]+ - one or more digit

$ - end of string

Upvotes: 0

Maheer Ali
Maheer Ali

Reputation: 36574

What I understood you want to validate +numbers. You should use ^ and $ in start of end of your regex. I think following regex will work if i am not wrong.

/^\+[0-9]+$/

Upvotes: 0

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