modify js-cookie support external cookie. 修改 js-cookie 让它支持了调用时输入 cookie 字串。移除了原有的模块化支持，仅保留 es6 模块化方案。

js-cookie.js

/*!
 * JavaScript Cookie v2.2.1
 * https://github.com/js-cookie/js-cookie
 *
 * Copyright 2006, 2015 Klaus Hartl & Fagner Brack
 * Released under the MIT license
 * 
 * 移植自 https://github.com/js-cookie/js-cookie 54962f8
 * 
 * 为 get/getJSON 方法增加了数据源的入参，方便服务端调用
 */
function extend() {
  var i = 0;
  var result = {};
  for (; i < arguments.length; i++) {
    var attributes = arguments[i];
    for (var key in attributes) {
      result[key] = attributes[key];
    }
  }
  return result;
}

function decode(s) {
  return s.replace(/(%[0-9A-Z]{2})+/g, decodeURIComponent);
}

function init(converter) {

  function set(key, value, attributes) {
    if (typeof document === 'undefined') {
      return;
    }

    attributes = extend({
      path: '/'
    }, api.defaults, attributes);

    if (typeof attributes.expires === 'number') {
      attributes.expires = new Date(new Date() * 1 + attributes.expires * 864e+5);
    }

    // We're using "expires" because "max-age" is not supported by IE
    attributes.expires = attributes.expires ? attributes.expires.toUTCString() : '';

    try {
      var result = JSON.stringify(value);
      if (/^[\{\[]/.test(result)) {
        value = result;
      }
    } catch (e) { }

    value = converter.write ?
      converter.write(value, key) :
      encodeURIComponent(String(value))
        .replace(/%(23|24|26|2B|3A|3C|3E|3D|2F|3F|40|5B|5D|5E|60|7B|7D|7C)/g, decodeURIComponent);

    key = encodeURIComponent(String(key))
      .replace(/%(23|24|26|2B|5E|60|7C)/g, decodeURIComponent)
      .replace(/[\(\)]/g, escape);

    var stringifiedAttributes = '';
    for (var attributeName in attributes) {
      if (!attributes[attributeName]) {
        continue;
      }
      stringifiedAttributes += '; ' + attributeName;
      if (attributes[attributeName] === true) {
        continue;
      }

      // Considers RFC 6265 section 5.2:
      // ...
      // 3.  If the remaining unparsed-attributes contains a %x3B (";")
      //     character:
      // Consume the characters of the unparsed-attributes up to,
      // not including, the first %x3B (";") character.
      // ...
      stringifiedAttributes += '=' + attributes[attributeName].split(';')[0];
    }

    return (document.cookie = key + '=' + value + stringifiedAttributes);
  }

  function get(key, json, source) {
    if (typeof document === 'undefined' && !source) {
      return;
    }

    var jar = {};
    // To prevent the for loop in the first place assign an empty array
    // in case there are no cookies at all.
    var cookies = source && source.split('; ') || (document.cookie ? document.cookie.split('; ') : []);
    var i = 0;

    for (; i < cookies.length; i++) {
      var parts = cookies[i].split('=');
      var cookie = parts.slice(1).join('=');

      if (!json && cookie.charAt(0) === '"') {
        cookie = cookie.slice(1, -1);
      }

      try {
        var name = decode(parts[0]);
        cookie = (converter.read || converter)(cookie, name) ||
          decode(cookie);

        if (json) {
          try {
            cookie = JSON.parse(cookie);
          } catch (e) { }
        }

        jar[name] = cookie;

        if (key === name) {
          break;
        }
      } catch (e) { }
    }

    return key ? jar[key] : jar;
  }

  function api() { }

  api.set = set;
  api.get = function (key, source) {
    return get(key, false, source /* read as raw */);
  };
  api.getJSON = function (key, source) {
    return get(key, true, source /* read as json */);
  };
  api.remove = function (key, attributes) {
    set(key, '', extend(attributes, {
      expires: -1
    }));
  };

  api.defaults = {};

  api.withConverter = init;

  return api;
}

export default init(function () { });

仅修改了 get 方法，给 get 方法增加了一个入参

让 get 支持从外部导入 cookie 字串，方便在 js 的服务端统一处理 cookie