formatParamUrl.js

/*
/some/:id/path => /some/{id}/path

/another/:example/for/:you => /another/{example}/for/{you}
*/

function formatParamUrl (url) {
  var start = url.indexOf('/:')
  if (start === -1) return url

  var end = url.indexOf('/', ++start)

  if (end === -1) {
    return url.slice(0, start) + '{' + url.slice(++start) + '}'
  } else {
    return formatParamUrl(url.slice(0, start) + '{' + url.slice(++start, end) + '}' + url.slice(end))
  }
}