Limit text to be selected from input with Javascript

Question

I would like to know how to limit the value to be selected with Javascript.

For example, I want to take only the country indicator of the number typed, but it is different the amount of characters for each country, type, Brazil has 3 "+55", whereas the United States has only 2 "+1".

How do I get the JS to select only this indicator from that code that selects the input value:

$(this). val();

Remembering that soon after the country indicator will come a "(", for example, "[phone]".

Answer 1

Here I am using the substring function that will return all the content in the string that exists before the character "(", that is, from position 0 to where there is the character I want to limit.

let numeroTelefone = '[phone]';
let codigoPais;
codigoPais = numeroTelefone.substring(0, numeroTelefone.indexOf("("));

In this case, only the string "+55 will be returned".

Answer 2

Using the regex below with .match() you can get the code:

\+\d{1,3}

The pattern will capture the + followed by 1 to 3 numbers.

Example:

$("input").on("focus", function(){
   
   var ddi = $(this).val().match(/\+\d{1,3}/)[0];
   console.log(ddi);
   
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
Clique num input abaixo:
<br>
<input type="text" readonly value="[phone]">
<br>
<input type="text" readonly value="[phone]">
<br>
<input type="text" readonly value="[phone]">