freeCodeCamp/curriculum/challenges/english/99-dev-playground/daily-coding-challenges-javascript/javascript-challenge-16.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
6821ebda237de8297eaee792	JavaScript Challenge 16: Reverse Parenthesis	28	javascript-challenge-16

--description--

Given a string that contains properly nested parentheses, return the decoded version of the string using the following rules:

• All characters inside each pair of parentheses should be reversed.
• Parentheses should be removed from the final result.
• If parentheses are nested, the innermost pair should be reversed first, and then its result should be included in the reversal of the outer pair.
• Assume all parentheses are evenly balanced and correctly nested.

--hints--

decode("(f(b(dc)e)a)") should return "abcdef".

assert.equal(decode("(f(b(dc)e)a)"), "abcdef");

decode("((is?)(a(t d)h)e(n y( uo)r)aC)") should return "Can you read this?".

assert.equal(decode("((is?)(a(t d)h)e(n y( uo)r)aC)"), "Can you read this?");

decode("f(Ce(re))o((e(aC)m)d)p") should return "freeCodeCamp".

assert.equal(decode("f(Ce(re))o((e(aC)m)d)p"), "freeCodeCamp");

--seed--

--seed-contents--

function decode(s) {

  return s;
}

--solutions--

function decode(s) {
  while (s.includes(')')) {
    const closeIndex = s.indexOf(')');
    const openIndex = s.lastIndexOf('(', closeIndex);
    const before = s.slice(0, openIndex);
    const group = s.slice(openIndex + 1, closeIndex).split('').reverse().join('');
    const after = s.slice(closeIndex + 1);
    s = before + group + after;
  }

  return s;
}