(Javascript) Remove param from url (standardjs)

index.js

const removeQueryVar = (key, url) => {
  let rtn = url.split('?')[0]
  let param
  let params = []
  let queryString = (url.indexOf('?') !== -1) ? url.split('?')[1] : ''

  if (queryString !== '') {
    params = queryString.split('&')
    for (var i = params.length - 1; i >= 0; i -= 1) {
      param = params[i].split('=')[0]
      if (param === key) {
        params.splice(i, 1)
      }
    }
    if (params.length) rtn = rtn + '?' + params.join('&')
  }
  return rtn
}

// Example use:
removeQueryVar('action', currentUrl)