How do I check for brackets in a specific place in the string?

Question

I have this code and it needs to returns true or false based on the string you give it. This is the only example on which it doesn't work. How can I check if brackets exist in a specific index of the string?

function telephoneCheck(str) {

var newStr = str.replace(/-/g,'').replace(/ /g,'').replace(/\(|\)/g,'');
var valid = true;
var re = /\([^()]*\)/g;
while (str.match(re))
    str = str.replace(re, '');
if (str.match(/[()]/)){
  valid = false;
}
if(newStr.length === 10 && valid === true && str.indexOf()){
  return true;
}else if(newStr.length === 11 && str[0] != "-" && newStr[0] == 1 && valid === true){
  return true;
}else{
  return false;
}
}

telephoneCheck("(6505552368)");

Answer 1

Based on your code I think you might be looking for something like this:

'(6505552368)'.replace(/^\((\d+)\)$/, '$1');

The ^ and $ in the RegExp will match the start and the end of the string. The \d+ will match one or more numbers. The extra parentheses form a capture group that is then used in the replacement as $1.

You might be better off doing more work using RegExps rather than doing all that replacing but without knowing the exact requirements it's difficult to be more precise. I highly suggest learning more about RegExp syntax.

If you literally just want to know whether 'brackets exist in a specific index' then you can just use:

str.charAt(index) === '(';

Answer 2

To check if there are brackets at a specific index in the string:

/[()]/.test(str[index])

To check if there are any brackets in the string at all:

/[()]/.test(str)

If you want to test for a specific bracket type (e.g. opening but not closing) remove the other one (e.g. closing) from the regex.