Function urlEncodeKeyValue

src/url.js:211–213

* @param {string} key * @param {string} value * @return {string}

(key, value)

 * @return {string}
 */
function urlEncodeKeyValue(key, value) {
  return `${encodeURIComponent(key)}=${encodeURIComponent(value)}`;
}

/**
 * Appends a query string field and value to a url. `key` and `value`