Is there a Javascript method that will achieve concatenation of nested parenthesis?

I am trying to create a string from input but formatted in a unique way.

Inputs will be single words: word1

The string will be empty until the first input comes then the string myString will be +(-word1).

For the second input: word2, myString needs to now look like:

    +(-word1+(-word2))

For clarity, a third input: word3, myString will now be:

    +(-word1+(-word2+(-word3)))

I believe this is going to require something a little more clever than normal string concatenation. I would prefer to not use a loop.

Is there a native Javascript (or potentially JQuery) function that can accomplish creating a string like this?

Here is what I have done

    var myString = '';

    function someFunction()
    { 
     ...

      var inputString = document.getElementById('my-input').value;
      myString = myString + "+(" + "-" + inputString + ")";
    }

However this is producing

    +(-word1)+(-word2)

This makes sense because the strings are just being concatenated in the function, what needs to happen rather is a sort of insertion. Is there a Javascript method that could make this insertion easier? Perhaps something like inserting the new string at the second to last space of the current string? However it's not an array so I don't know best practices here.

HERE IS THe SOLUTION

You look for the first closing parentesis and replace the value.

const insert = (s, v) => s ? s.replace(/(?=\))/, `+(-${v})`) : `+(-${v})`;

console.log(['word1', 'word2', 'word3'].reduce(insert, undefined));