Function getAdapter

lib/adapters/adapters.js:65–115

* Get the first suitable adapter from the provided list. * Tries each adapter in order until a supported one is found. * Throws an AxiosError if no adapter is suitable. * * @param {Array<string|Function>|string|Function} adapters - Adapter(s) by name or function. * @param {Object} config - Axio

(adapters, config)

 * @returns {Function} The resolved adapter function
 */
function getAdapter(adapters, config) {
  adapters = utils.isArray(adapters) ? adapters : [adapters];

  const { length } = adapters;
  let nameOrAdapter;
  let adapter;

  const rejectedReasons = {};

  for (let i = 0; i < length; i++) {
    nameOrAdapter = adapters[i];
    let id;

    adapter = nameOrAdapter;

    if (!isResolvedHandle(nameOrAdapter)) {
      adapter = knownAdapters[(id = String(nameOrAdapter)).toLowerCase()];

      if (adapter === undefined) {
        throw new AxiosError(`Unknown adapter '${id}'`);
      }
    }

    if (adapter && (utils.isFunction(adapter) || (adapter = adapter.get(config)))) {
      break;
    }

    rejectedReasons[id || '#' + i] = adapter;
  }

  if (!adapter) {
    const reasons = Object.entries(rejectedReasons).map(
      ([id, state]) =>
        `adapter ${id} ` +
        (state === false ? 'is not supported by the environment' : 'is not available in the build')
    );

    let s = length
      ? reasons.length > 1
        ? 'since :\n' + reasons.map(renderReason).join('\n')
        : ' ' + renderReason(reasons[0])
      : 'as no adapter specified';

    throw new AxiosError(
      `There is no suitable adapter to dispatch the request ` + s,
      AxiosError.ERR_NOT_SUPPORT
    );
  }

  return adapter;
}

/**
 * Exports Axios adapters and utility to resolve an adapter