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View File Name : vue-meta.js

/**
 * vue-meta v2.4.0
 * (c) 2020
 * - Declan de Wet
 * - Sébastien Chopin (@Atinux)
 * - Pim (@pimlie)
 * - All the amazing contributors
 * @license MIT
 */

(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global = global || self, global.VueMeta = factory());
}(this, (function () { 'use strict';

  var version = "2.4.0";

  function _typeof(obj) {
    "@babel/helpers - typeof";

    if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") {
      _typeof = function (obj) {
        return typeof obj;
      };
    } else {
      _typeof = function (obj) {
        return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj;
      };
    }

    return _typeof(obj);
  }

  function _unsupportedIterableToArray(o, minLen) {
    if (!o) return;
    if (typeof o === "string") return _arrayLikeToArray(o, minLen);
    var n = Object.prototype.toString.call(o).slice(8, -1);
    if (n === "Object" && o.constructor) n = o.constructor.name;
    if (n === "Map" || n === "Set") return Array.from(o);
    if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen);
  }

  function _arrayLikeToArray(arr, len) {
    if (len == null || len > arr.length) len = arr.length;

    for (var i = 0, arr2 = new Array(len); i < len; i++) arr2[i] = arr[i];

    return arr2;
  }

  function _createForOfIteratorHelper(o, allowArrayLike) {
    var it;

    if (typeof Symbol === "undefined" || o[Symbol.iterator] == null) {
      if (Array.isArray(o) || (it = _unsupportedIterableToArray(o)) || allowArrayLike && o && typeof o.length === "number") {
        if (it) o = it;
        var i = 0;

        var F = function () {};

        return {
          s: F,
          n: function () {
            if (i >= o.length) return {
              done: true
            };
            return {
              done: false,
              value: o[i++]
            };
          },
          e: function (e) {
            throw e;
          },
          f: F
        };
      }

      throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method.");
    }

    var normalCompletion = true,
        didErr = false,
        err;
    return {
      s: function () {
        it = o[Symbol.iterator]();
      },
      n: function () {
        var step = it.next();
        normalCompletion = step.done;
        return step;
      },
      e: function (e) {
        didErr = true;
        err = e;
      },
      f: function () {
        try {
          if (!normalCompletion && it.return != null) it.return();
        } finally {
          if (didErr) throw err;
        }
      }
    };
  }

  /**
   * checks if passed argument is an array
   * @param  {any}  arg - the object to check
   * @return {Boolean} - true if `arg` is an array
   */
  function isArray(arg) {
    return Array.isArray(arg);
  }
  function isUndefined(arg) {
    return typeof arg === 'undefined';
  }
  function isObject(arg) {
    return _typeof(arg) === 'object';
  }
  function isPureObject(arg) {
    return _typeof(arg) === 'object' && arg !== null;
  }
  function isFunction(arg) {
    return typeof arg === 'function';
  }
  function isString(arg) {
    return typeof arg === 'string';
  }

  function hasGlobalWindowFn() {
    try {
      return !isUndefined(window);
    } catch (e) {
      return false;
    }
  }
  var hasGlobalWindow = hasGlobalWindowFn();

  var _global = hasGlobalWindow ? window : global;

  var console = _global.console || {};
  function warn(str) {
    /* istanbul ignore next */
    if (!console || !console.warn) {
      return;
    }

    console.warn(str);
  }
  var showWarningNotSupportedInBrowserBundle = function showWarningNotSupportedInBrowserBundle(method) {
    return warn("".concat(method, " is not supported in browser builds"));
  };
  var showWarningNotSupported = function showWarningNotSupported() {
    return warn('This vue app/component has no vue-meta configuration');
  };

  /**
   * These are constant variables used throughout the application.
   */
  // set some sane defaults
  var defaultInfo = {
    title: undefined,
    titleChunk: '',
    titleTemplate: '%s',
    htmlAttrs: {},
    bodyAttrs: {},
    headAttrs: {},
    base: [],
    link: [],
    meta: [],
    style: [],
    script: [],
    noscript: [],
    __dangerouslyDisableSanitizers: [],
    __dangerouslyDisableSanitizersByTagID: {}
  };
  var rootConfigKey = '_vueMeta'; // This is the name of the component option that contains all the information that
  // gets converted to the various meta tags & attributes for the page.

  var keyName = 'metaInfo'; // This is the attribute vue-meta arguments on elements to know which it should
  // manage and which it should ignore.

  var attribute = 'data-vue-meta'; // This is the attribute that goes on the `html` tag to inform `vue-meta`
  // that the server has already generated the meta tags for the initial render.

  var ssrAttribute = 'data-vue-meta-server-rendered'; // This is the property that tells vue-meta to overwrite (instead of append)
  // an item in a tag list. For example, if you have two `meta` tag list items
  // that both have `vmid` of "description", then vue-meta will overwrite the
  // shallowest one with the deepest one.

  var tagIDKeyName = 'vmid'; // This is the key name for possible meta templates

  var metaTemplateKeyName = 'template'; // This is the key name for the content-holding property

  var contentKeyName = 'content'; // The id used for the ssr app

  var ssrAppId = 'ssr'; // How long meta update

  var debounceWait = 10; // How long meta update

  var waitOnDestroyed = true;
  var defaultOptions = {
    keyName: keyName,
    attribute: attribute,
    ssrAttribute: ssrAttribute,
    tagIDKeyName: tagIDKeyName,
    contentKeyName: contentKeyName,
    metaTemplateKeyName: metaTemplateKeyName,
    waitOnDestroyed: waitOnDestroyed,
    debounceWait: debounceWait,
    ssrAppId: ssrAppId
  }; // might be a bit ugly, but minimizes the browser bundles a bit

  var defaultInfoKeys = Object.keys(defaultInfo); // The metaInfo property keys which are used to disable escaping

  var disableOptionKeys = [defaultInfoKeys[12], defaultInfoKeys[13]]; // List of metaInfo property keys which are configuration options (and dont generate html)

  var metaInfoOptionKeys = [defaultInfoKeys[1], defaultInfoKeys[2], 'changed'].concat(disableOptionKeys); // List of metaInfo property keys which only generates attributes and no tags

  var metaInfoAttributeKeys = [defaultInfoKeys[3], defaultInfoKeys[4], defaultInfoKeys[5]]; // HTML elements which support the onload event

  var tagsSupportingOnload = ['link', 'style', 'script']; // HTML elements which dont have a head tag (shortened to our needs)
  var tagProperties = ['once', 'skip', 'template']; // Attributes which should be added with data- prefix

  var commonDataAttributes = ['body', 'pbody']; // from: https://github.com/kangax/html-minifier/blob/gh-pages/src/htmlminifier.js#L202

  var booleanHtmlAttributes = ['allowfullscreen', 'amp', 'amp-boilerplate', 'async', 'autofocus', 'autoplay', 'checked', 'compact', 'controls', 'declare', 'default', 'defaultchecked', 'defaultmuted', 'defaultselected', 'defer', 'disabled', 'enabled', 'formnovalidate', 'hidden', 'indeterminate', 'inert', 'ismap', 'itemscope', 'loop', 'multiple', 'muted', 'nohref', 'noresize', 'noshade', 'novalidate', 'nowrap', 'open', 'pauseonexit', 'readonly', 'required', 'reversed', 'scoped', 'seamless', 'selected', 'sortable', 'truespeed', 'typemustmatch', 'visible'];

  var batchId = null;
  function triggerUpdate(_ref, rootVm, hookName) {
    var debounceWait = _ref.debounceWait;

    // if an update was triggered during initialization or when an update was triggered by the
    // metaInfo watcher, set initialized to null
    // then we keep falsy value but know we need to run a triggerUpdate after initialization
    if (!rootVm[rootConfigKey].initialized && (rootVm[rootConfigKey].initializing || hookName === 'watcher')) {
      rootVm[rootConfigKey].initialized = null;
    }

    if (rootVm[rootConfigKey].initialized && !rootVm[rootConfigKey].pausing) {
      // batch potential DOM updates to prevent extraneous re-rendering
      // eslint-disable-next-line no-void
      batchUpdate(function () {
        return void rootVm.$meta().refresh();
      }, debounceWait);
    }
  }
  /**
   * Performs a batched update.
   *
   * @param  {(null|Number)} id - the ID of this update
   * @param  {Function} callback - the update to perform
   * @return {Number} id - a new ID
   */

  function batchUpdate(callback, timeout) {
    timeout = timeout === undefined ? 10 : timeout;

    if (!timeout) {
      callback();
      return;
    }

    clearTimeout(batchId);
    batchId = setTimeout(function () {
      callback();
    }, timeout);
    return batchId;
  }

  /*
   * To reduce build size, this file provides simple polyfills without
   * overly excessive type checking and without modifying
   * the global Array.prototype
   * The polyfills are automatically removed in the commonjs build
   * Also, only files in client/ & shared/ should use these functions
   * files in server/ still use normal js function
   */
  function find(array, predicate, thisArg) {
    if ( !Array.prototype.find) {
      // idx needs to be a Number, for..in returns string
      for (var idx = 0; idx < array.length; idx++) {
        if (predicate.call(thisArg, array[idx], idx, array)) {
          return array[idx];
        }
      }

      return;
    }

    return array.find(predicate, thisArg);
  }
  function findIndex(array, predicate, thisArg) {
    if ( !Array.prototype.findIndex) {
      // idx needs to be a Number, for..in returns string
      for (var idx = 0; idx < array.length; idx++) {
        if (predicate.call(thisArg, array[idx], idx, array)) {
          return idx;
        }
      }

      return -1;
    }

    return array.findIndex(predicate, thisArg);
  }
  function toArray(arg) {
    if ( !Array.from) {
      return Array.prototype.slice.call(arg);
    }

    return Array.from(arg);
  }
  function includes(array, value) {
    if ( !Array.prototype.includes) {
      for (var idx in array) {
        if (array[idx] === value) {
          return true;
        }
      }

      return false;
    }

    return array.includes(value);
  }

  var querySelector = function querySelector(arg, el) {
    return (el || document).querySelectorAll(arg);
  };
  function getTag(tags, tag) {
    if (!tags[tag]) {
      tags[tag] = document.getElementsByTagName(tag)[0];
    }

    return tags[tag];
  }
  function getElementsKey(_ref) {
    var body = _ref.body,
        pbody = _ref.pbody;
    return body ? 'body' : pbody ? 'pbody' : 'head';
  }
  function queryElements(parentNode, _ref2, attributes) {
    var appId = _ref2.appId,
        attribute = _ref2.attribute,
        type = _ref2.type,
        tagIDKeyName = _ref2.tagIDKeyName;
    attributes = attributes || {};
    var queries = ["".concat(type, "[").concat(attribute, "=\"").concat(appId, "\"]"), "".concat(type, "[data-").concat(tagIDKeyName, "]")].map(function (query) {
      for (var key in attributes) {
        var val = attributes[key];
        var attributeValue = val && val !== true ? "=\"".concat(val, "\"") : '';
        query += "[data-".concat(key).concat(attributeValue, "]");
      }

      return query;
    });
    return toArray(querySelector(queries.join(', '), parentNode));
  }
  function removeElementsByAppId(_ref3, appId) {
    var attribute = _ref3.attribute;
    toArray(querySelector("[".concat(attribute, "=\"").concat(appId, "\"]"))).map(function (el) {
      return el.remove();
    });
  }
  function removeAttribute(el, attributeName) {
    el.removeAttribute(attributeName);
  }

  function hasMetaInfo(vm) {
    vm = vm || this;
    return vm && (vm[rootConfigKey] === true || isObject(vm[rootConfigKey]));
  } // a component is in a metaInfo branch when itself has meta info or one of its (grand-)children has

  function inMetaInfoBranch(vm) {
    vm = vm || this;
    return vm && !isUndefined(vm[rootConfigKey]);
  }

  function pause(rootVm, refresh) {
    rootVm[rootConfigKey].pausing = true;
    return function () {
      return resume(rootVm, refresh);
    };
  }
  function resume(rootVm, refresh) {
    rootVm[rootConfigKey].pausing = false;

    if (refresh || refresh === undefined) {
      return rootVm.$meta().refresh();
    }
  }

  function addNavGuards(rootVm) {
    var router = rootVm.$router; // return when nav guards already added or no router exists

    if (rootVm[rootConfigKey].navGuards || !router) {
      /* istanbul ignore next */
      return;
    }

    rootVm[rootConfigKey].navGuards = true;
    router.beforeEach(function (to, from, next) {
      pause(rootVm);
      next();
    });
    router.afterEach(function () {
      rootVm.$nextTick(function () {
        var _resume = resume(rootVm),
            metaInfo = _resume.metaInfo;

        if (metaInfo && isFunction(metaInfo.afterNavigation)) {
          metaInfo.afterNavigation(metaInfo);
        }
      });
    });
  }

  var appId = 1;
  function createMixin(Vue, options) {
    // for which Vue lifecycle hooks should the metaInfo be refreshed
    var updateOnLifecycleHook = ['activated', 'deactivated', 'beforeMount'];
    var wasServerRendered = false; // watch for client side component updates

    return {
      beforeCreate: function beforeCreate() {
        var _this2 = this;

        var rootKey = '$root';
        var $root = this[rootKey];
        var $options = this.$options;
        var devtoolsEnabled = Vue.config.devtools;
        Object.defineProperty(this, '_hasMetaInfo', {
          configurable: true,
          get: function get() {
            // Show deprecation warning once when devtools enabled
            if (devtoolsEnabled && !$root[rootConfigKey].deprecationWarningShown) {
              warn('VueMeta DeprecationWarning: _hasMetaInfo has been deprecated and will be removed in a future version. Please use hasMetaInfo(vm) instead');
              $root[rootConfigKey].deprecationWarningShown = true;
            }

            return hasMetaInfo(this);
          }
        });

        if (this === $root) {
          $root.$once('hook:beforeMount', function () {
            wasServerRendered = this.$el && this.$el.nodeType === 1 && this.$el.hasAttribute('data-server-rendered'); // In most cases when you have a SSR app it will be the first app thats gonna be
            // initiated, if we cant detect the data-server-rendered attribute from Vue but we
            // do see our own ssrAttribute then _assume_ the Vue app with appId 1 is the ssr app
            // attempted fix for #404 & #562, but we rly need to refactor how we pass appIds from
            // ssr to the client

            if (!wasServerRendered && $root[rootConfigKey] && $root[rootConfigKey].appId === 1) {
              var htmlTag = getTag({}, 'html');
              wasServerRendered = htmlTag && htmlTag.hasAttribute(options.ssrAttribute);
            }
          });
        } // Add a marker to know if it uses metaInfo
        // _vnode is used to know that it's attached to a real component
        // useful if we use some mixin to add some meta tags (like nuxt-i18n)


        if (isUndefined($options[options.keyName]) || $options[options.keyName] === null) {
          return;
        }

        if (!$root[rootConfigKey]) {
          $root[rootConfigKey] = {
            appId: appId
          };
          appId++;

          if (devtoolsEnabled && $root.$options[options.keyName]) {
            // use nextTick so the children should be added to $root
            this.$nextTick(function () {
              // find the first child that lists fnOptions
              var child = find($root.$children, function (c) {
                return c.$vnode && c.$vnode.fnOptions;
              });

              if (child && child.$vnode.fnOptions[options.keyName]) {
                warn("VueMeta has detected a possible global mixin which adds a ".concat(options.keyName, " property to all Vue components on the page. This could cause severe performance issues. If possible, use $meta().addApp to add meta information instead"));
              }
            });
          }
        } // to speed up updates we keep track of branches which have a component with vue-meta info defined
        // if _vueMeta = true it has info, if _vueMeta = false a child has info


        if (!this[rootConfigKey]) {
          this[rootConfigKey] = true;
          var parent = this.$parent;

          while (parent && parent !== $root) {
            if (isUndefined(parent[rootConfigKey])) {
              parent[rootConfigKey] = false;
            }

            parent = parent.$parent;
          }
        } // coerce function-style metaInfo to a computed prop so we can observe
        // it on creation


        if (isFunction($options[options.keyName])) {
          $options.computed = $options.computed || {};
          $options.computed.$metaInfo = $options[options.keyName];

          if (!this.$isServer) {
            // if computed $metaInfo exists, watch it for updates & trigger a refresh
            // when it changes (i.e. automatically handle async actions that affect metaInfo)
            // credit for this suggestion goes to [Sébastien Chopin](https://github.com/Atinux)
            this.$on('hook:created', function () {
              this.$watch('$metaInfo', function () {
                triggerUpdate(options, this[rootKey], 'watcher');
              });
            });
          }
        } // force an initial refresh on page load and prevent other lifecycleHooks
        // to triggerUpdate until this initial refresh is finished
        // this is to make sure that when a page is opened in an inactive tab which
        // has throttled rAF/timers we still immediately set the page title


        if (isUndefined($root[rootConfigKey].initialized)) {
          $root[rootConfigKey].initialized = this.$isServer;

          if (!$root[rootConfigKey].initialized) {
            if (!$root[rootConfigKey].initializedSsr) {
              $root[rootConfigKey].initializedSsr = true;
              this.$on('hook:beforeMount', function () {
                var $root = this[rootKey]; // if this Vue-app was server rendered, set the appId to 'ssr'
                // only one SSR app per page is supported

                if (wasServerRendered) {
                  $root[rootConfigKey].appId = options.ssrAppId;
                }
              });
            } // we use the mounted hook here as on page load


            this.$on('hook:mounted', function () {
              var $root = this[rootKey];

              if ($root[rootConfigKey].initialized) {
                return;
              } // used in triggerUpdate to check if a change was triggered
              // during initialization


              $root[rootConfigKey].initializing = true; // refresh meta in nextTick so all child components have loaded

              this.$nextTick(function () {
                var _$root$$meta$refresh = $root.$meta().refresh(),
                    tags = _$root$$meta$refresh.tags,
                    metaInfo = _$root$$meta$refresh.metaInfo; // After ssr hydration (identifier by tags === false) check
                // if initialized was set to null in triggerUpdate. That'd mean
                // that during initilazation changes where triggered which need
                // to be applied OR a metaInfo watcher was triggered before the
                // current hook was called
                // (during initialization all changes are blocked)


                if (tags === false && $root[rootConfigKey].initialized === null) {
                  this.$nextTick(function () {
                    return triggerUpdate(options, $root, 'init');
                  });
                }

                $root[rootConfigKey].initialized = true;
                delete $root[rootConfigKey].initializing; // add the navigation guards if they havent been added yet
                // they are needed for the afterNavigation callback

                if (!options.refreshOnceOnNavigation && metaInfo.afterNavigation) {
                  addNavGuards($root);
                }
              });
            }); // add the navigation guards if requested

            if (options.refreshOnceOnNavigation) {
              addNavGuards($root);
            }
          }
        }

        this.$on('hook:destroyed', function () {
          var _this = this;

          // do not trigger refresh:
          // - when user configured to not wait for transitions on destroyed
          // - when the component doesnt have a parent
          // - doesnt have metaInfo defined
          if (!this.$parent || !hasMetaInfo(this)) {
            return;
          }

          delete this._hasMetaInfo;
          this.$nextTick(function () {
            if (!options.waitOnDestroyed || !_this.$el || !_this.$el.offsetParent) {
              triggerUpdate(options, _this.$root, 'destroyed');
              return;
            } // Wait that element is hidden before refreshing meta tags (to support animations)


            var interval = setInterval(function () {
              if (_this.$el && _this.$el.offsetParent !== null) {
                /* istanbul ignore next line */
                return;
              }

              clearInterval(interval);
              triggerUpdate(options, _this.$root, 'destroyed');
            }, 50);
          });
        }); // do not trigger refresh on the server side

        if (this.$isServer) {
          /* istanbul ignore next */
          return;
        } // no need to add this hooks on server side


        updateOnLifecycleHook.forEach(function (lifecycleHook) {
          _this2.$on("hook:".concat(lifecycleHook), function () {
            triggerUpdate(options, this[rootKey], lifecycleHook);
          });
        });
      }
    };
  }

  function setOptions(options) {
    // combine options
    options = isObject(options) ? options : {}; // The options are set like this so they can
    // be minified by terser while keeping the
    // user api intact
    // terser --mangle-properties keep_quoted=strict

    /* eslint-disable dot-notation */

    return {
      keyName: options['keyName'] || defaultOptions.keyName,
      attribute: options['attribute'] || defaultOptions.attribute,
      ssrAttribute: options['ssrAttribute'] || defaultOptions.ssrAttribute,
      tagIDKeyName: options['tagIDKeyName'] || defaultOptions.tagIDKeyName,
      contentKeyName: options['contentKeyName'] || defaultOptions.contentKeyName,
      metaTemplateKeyName: options['metaTemplateKeyName'] || defaultOptions.metaTemplateKeyName,
      debounceWait: isUndefined(options['debounceWait']) ? defaultOptions.debounceWait : options['debounceWait'],
      waitOnDestroyed: isUndefined(options['waitOnDestroyed']) ? defaultOptions.waitOnDestroyed : options['waitOnDestroyed'],
      ssrAppId: options['ssrAppId'] || defaultOptions.ssrAppId,
      refreshOnceOnNavigation: !!options['refreshOnceOnNavigation']
    };
    /* eslint-enable dot-notation */
  }
  function getOptions(options) {
    var optionsCopy = {};

    for (var key in options) {
      optionsCopy[key] = options[key];
    }

    return optionsCopy;
  }

  function ensureIsArray(arg, key) {
    if (!key || !isObject(arg)) {
      return isArray(arg) ? arg : [];
    }

    if (!isArray(arg[key])) {
      arg[key] = [];
    }

    return arg;
  }

  var clientSequences = [[/&/g, "&"], [/</g, "<"], [/>/g, ">"], [/"/g, "\""], [/'/g, "'"]]; // sanitizes potentially dangerous characters

  function escape(info, options, escapeOptions, escapeKeys) {
    var tagIDKeyName = options.tagIDKeyName;
    var _escapeOptions$doEsca = escapeOptions.doEscape,
        doEscape = _escapeOptions$doEsca === void 0 ? function (v) {
      return v;
    } : _escapeOptions$doEsca;
    var escaped = {};

    for (var key in info) {
      var value = info[key]; // no need to escape configuration options

      if (includes(metaInfoOptionKeys, key)) {
        escaped[key] = value;
        continue;
      } // do not use destructuring for disableOptionKeys, it increases transpiled size
      // due to var checks while we are guaranteed the structure of the cb


      var disableKey = disableOptionKeys[0];

      if (escapeOptions[disableKey] && includes(escapeOptions[disableKey], key)) {
        // this info[key] doesnt need to escaped if the option is listed in __dangerouslyDisableSanitizers
        escaped[key] = value;
        continue;
      }

      var tagId = info[tagIDKeyName];

      if (tagId) {
        disableKey = disableOptionKeys[1]; // keys which are listed in __dangerouslyDisableSanitizersByTagID for the current vmid do not need to be escaped

        if (escapeOptions[disableKey] && escapeOptions[disableKey][tagId] && includes(escapeOptions[disableKey][tagId], key)) {
          escaped[key] = value;
          continue;
        }
      }

      if (isString(value)) {
        escaped[key] = doEscape(value);
      } else if (isArray(value)) {
        escaped[key] = value.map(function (v) {
          if (isPureObject(v)) {
            return escape(v, options, escapeOptions, true);
          }

          return doEscape(v);
        });
      } else if (isPureObject(value)) {
        escaped[key] = escape(value, options, escapeOptions, true);
      } else {
        escaped[key] = value;
      }

      if (escapeKeys) {
        var escapedKey = doEscape(key);

        if (key !== escapedKey) {
          escaped[escapedKey] = escaped[key];
          delete escaped[key];
        }
      }
    }

    return escaped;
  }
  function escapeMetaInfo(options, info, escapeSequences) {
    escapeSequences = escapeSequences || []; // do not use destructuring for seq, it increases transpiled size
    // due to var checks while we are guaranteed the structure of the cb

    var escapeOptions = {
      doEscape: function doEscape(value) {
        return escapeSequences.reduce(function (val, seq) {
          return val.replace(seq[0], seq[1]);
        }, value);
      }
    };
    disableOptionKeys.forEach(function (disableKey, index) {
      if (index === 0) {
        ensureIsArray(info, disableKey);
      } else if (index === 1) {
        for (var key in info[disableKey]) {
          ensureIsArray(info[disableKey], key);
        }
      }

      escapeOptions[disableKey] = info[disableKey];
    }); // begin sanitization

    return escape(info, options, escapeOptions);
  }

  var isMergeableObject = function isMergeableObject(value) {
    return isNonNullObject(value) && !isSpecial(value);
  };

  function isNonNullObject(value) {
    return !!value && _typeof(value) === 'object';
  }

  function isSpecial(value) {
    var stringValue = Object.prototype.toString.call(value);
    return stringValue === '[object RegExp]' || stringValue === '[object Date]' || false;
  } // see https://github.com/facebook/react/blob/b5ac963fb791d1298e7f396236383bc955f916c1/src/isomorphic/classic/element/ReactElement.js#L21-L25

  function cloneUnlessOtherwiseSpecified(value, options) {
    return  value;
  }

  function getMergeFunction(key, options) {
    {
      return deepmerge;
    }
  }

  function getKeys(target) {
    return Object.keys(target);
  }

  function propertyIsOnObject(object, property) {
    try {
      return property in object;
    } catch (_) {
      return false;
    }
  } // Protects from prototype poisoning and unexpected merging up the prototype chain.


  function propertyIsUnsafe(target, key) {
    return propertyIsOnObject(target, key) // Properties are safe to merge if they don't exist in the target yet,
    && !(Object.hasOwnProperty.call(target, key) // unsafe if they exist up the prototype chain,
    && Object.propertyIsEnumerable.call(target, key)); // and also unsafe if they're nonenumerable.
  }

  function mergeObject(target, source, options) {
    var destination = {};

    if (options.isMergeableObject(target)) {
      getKeys(target).forEach(function (key) {
        destination[key] = cloneUnlessOtherwiseSpecified(target[key]);
      });
    }

    getKeys(source).forEach(function (key) {
      if (propertyIsUnsafe(target, key)) {
        return;
      }

      if (propertyIsOnObject(target, key) && options.isMergeableObject(source[key])) {
        destination[key] = getMergeFunction()(target[key], source[key], options);
      } else {
        destination[key] = cloneUnlessOtherwiseSpecified(source[key]);
      }
    });
    return destination;
  }

  function deepmerge(target, source, options) {
    options = options || {};
    options.arrayMerge = options.arrayMerge;
    options.isMergeableObject = options.isMergeableObject || isMergeableObject; // cloneUnlessOtherwiseSpecified is added to `options` so that custom arrayMerge()
    // implementations can use it. The caller may not replace it.

    options.cloneUnlessOtherwiseSpecified = cloneUnlessOtherwiseSpecified;
    var sourceIsArray = Array.isArray(source);
    var targetIsArray = Array.isArray(target);
    var sourceAndTargetTypesMatch = sourceIsArray === targetIsArray;

    if (!sourceAndTargetTypesMatch) {
      return cloneUnlessOtherwiseSpecified(source);
    } else if (sourceIsArray) {
      return options.arrayMerge(target, source, options);
    } else {
      return mergeObject(target, source, options);
    }
  }
  var deepmerge_1 = deepmerge;
  var cjs = deepmerge_1;

  function applyTemplate(_ref, headObject, template, chunk) {
    var component = _ref.component,
        metaTemplateKeyName = _ref.metaTemplateKeyName,
        contentKeyName = _ref.contentKeyName;

    if (template === true || headObject[metaTemplateKeyName] === true) {
      // abort, template was already applied
      return false;
    }

    if (isUndefined(template) && headObject[metaTemplateKeyName]) {
      template = headObject[metaTemplateKeyName];
      headObject[metaTemplateKeyName] = true;
    } // return early if no template defined


    if (!template) {
      // cleanup faulty template properties
      delete headObject[metaTemplateKeyName];
      return false;
    }

    if (isUndefined(chunk)) {
      chunk = headObject[contentKeyName];
    }

    headObject[contentKeyName] = isFunction(template) ? template.call(component, chunk) : template.replace(/%s/g, chunk);
    return true;
  }

  function _arrayMerge(_ref, target, source) {
    var component = _ref.component,
        tagIDKeyName = _ref.tagIDKeyName,
        metaTemplateKeyName = _ref.metaTemplateKeyName,
        contentKeyName = _ref.contentKeyName;
    // we concat the arrays without merging objects contained in,
    // but we check for a `vmid` property on each object in the array
    // using an O(1) lookup associative array exploit
    var destination = [];

    if (!target.length && !source.length) {
      return destination;
    }

    target.forEach(function (targetItem, targetIndex) {
      // no tagID so no need to check for duplicity
      if (!targetItem[tagIDKeyName]) {
        destination.push(targetItem);
        return;
      }

      var sourceIndex = findIndex(source, function (item) {
        return item[tagIDKeyName] === targetItem[tagIDKeyName];
      });
      var sourceItem = source[sourceIndex]; // source doesnt contain any duplicate vmid's, we can keep targetItem

      if (sourceIndex === -1) {
        destination.push(targetItem);
        return;
      } // when sourceItem explictly defines contentKeyName or innerHTML as undefined, its
      // an indication that we need to skip the default behaviour or child has preference over parent
      // which means we keep the targetItem and ignore/remove the sourceItem


      if (contentKeyName in sourceItem && sourceItem[contentKeyName] === undefined || 'innerHTML' in sourceItem && sourceItem.innerHTML === undefined) {
        destination.push(targetItem); // remove current index from source array so its not concatenated to destination below

        source.splice(sourceIndex, 1);
        return;
      } // we now know that targetItem is a duplicate and we should ignore it in favor of sourceItem
      // if source specifies null as content then ignore both the target as the source


      if (sourceItem[contentKeyName] === null || sourceItem.innerHTML === null) {
        // remove current index from source array so its not concatenated to destination below
        source.splice(sourceIndex, 1);
        return;
      } // now we only need to check if the target has a template to combine it with the source


      var targetTemplate = targetItem[metaTemplateKeyName];

      if (!targetTemplate) {
        return;
      }

      var sourceTemplate = sourceItem[metaTemplateKeyName];

      if (!sourceTemplate) {
        // use parent template and child content
        applyTemplate({
          component: component,
          metaTemplateKeyName: metaTemplateKeyName,
          contentKeyName: contentKeyName
        }, sourceItem, targetTemplate); // set template to true to indicate template was already applied

        sourceItem.template = true;
        return;
      }

      if (!sourceItem[contentKeyName]) {
        // use parent content and child template
        applyTemplate({
          component: component,
          metaTemplateKeyName: metaTemplateKeyName,
          contentKeyName: contentKeyName
        }, sourceItem, undefined, targetItem[contentKeyName]);
      }
    });
    return destination.concat(source);
  }
  var warningShown = false;
  function merge(target, source, options) {
    options = options || {}; // remove properties explicitly set to false so child components can
    // optionally _not_ overwrite the parents content
    // (for array properties this is checked in arrayMerge)

    if (source.title === undefined) {
      delete source.title;
    }

    metaInfoAttributeKeys.forEach(function (attrKey) {
      if (!source[attrKey]) {
        return;
      }

      for (var key in source[attrKey]) {
        if (key in source[attrKey] && source[attrKey][key] === undefined) {
          if (includes(booleanHtmlAttributes, key) && !warningShown) {
            warn('VueMeta: Please note that since v2 the value undefined is not used to indicate boolean attributes anymore, see migration guide for details');
            warningShown = true;
          }

          delete source[attrKey][key];
        }
      }
    });
    return cjs(target, source, {
      arrayMerge: function arrayMerge(t, s) {
        return _arrayMerge(options, t, s);
      }
    });
  }

  function getComponentMetaInfo(options, component) {
    return getComponentOption(options || {}, component, defaultInfo);
  }
  /**
   * Returns the `opts.option` $option value of the given `opts.component`.
   * If methods are encountered, they will be bound to the component context.
   * If `opts.deep` is true, will recursively merge all child component
   * `opts.option` $option values into the returned result.
   *
   * @param  {Object} opts - options
   * @param  {Object} opts.component - Vue component to fetch option data from
   * @param  {Boolean} opts.deep - look for data in child components as well?
   * @param  {Function} opts.arrayMerge - how should arrays be merged?
   * @param  {String} opts.keyName - the name of the option to look for
   * @param  {Object} [result={}] - result so far
   * @return {Object} result - final aggregated result
   */

  function getComponentOption(options, component, result) {
    result = result || {};

    if (component._inactive) {
      return result;
    }

    options = options || {};
    var _options = options,
        keyName = _options.keyName;
    var $metaInfo = component.$metaInfo,
        $options = component.$options,
        $children = component.$children; // only collect option data if it exists

    if ($options[keyName]) {
      // if $metaInfo exists then [keyName] was defined as a function
      // and set to the computed prop $metaInfo in the mixin
      // using the computed prop should be a small performance increase
      // because Vue caches those internally
      var data = $metaInfo || $options[keyName]; // only merge data with result when its an object
      // eg it could be a function when metaInfo() returns undefined
      // dueo to the or statement above

      if (isObject(data)) {
        result = merge(result, data, options);
      }
    } // collect & aggregate child options if deep = true


    if ($children.length) {
      $children.forEach(function (childComponent) {
        // check if the childComponent is in a branch
        // return otherwise so we dont walk all component branches unnecessarily
        if (!inMetaInfoBranch(childComponent)) {
          return;
        }

        result = getComponentOption(options, childComponent, result);
      });
    }

    return result;
  }

  var callbacks = [];
  function isDOMComplete(d) {
    return (d || document).readyState === 'complete';
  }
  function addCallback(query, callback) {
    if (arguments.length === 1) {
      callback = query;
      query = '';
    }

    callbacks.push([query, callback]);
  }
  function addCallbacks(_ref, type, tags, autoAddListeners) {
    var tagIDKeyName = _ref.tagIDKeyName;
    var hasAsyncCallback = false;
    tags.forEach(function (tag) {
      if (!tag[tagIDKeyName] || !tag.callback) {
        return;
      }

      hasAsyncCallback = true;
      addCallback("".concat(type, "[data-").concat(tagIDKeyName, "=\"").concat(tag[tagIDKeyName], "\"]"), tag.callback);
    });

    if (!autoAddListeners || !hasAsyncCallback) {
      return hasAsyncCallback;
    }

    return addListeners();
  }
  function addListeners() {
    if (isDOMComplete()) {
      applyCallbacks();
      return;
    } // Instead of using a MutationObserver, we just apply

    /* istanbul ignore next */


    document.onreadystatechange = function () {
      applyCallbacks();
    };
  }
  function applyCallbacks(matchElement) {
    callbacks.forEach(function (args) {
      // do not use destructuring for args, it increases transpiled size
      // due to var checks while we are guaranteed the structure of the cb
      var query = args[0];
      var callback = args[1];
      var selector = "".concat(query, "[onload=\"this.__vm_l=1\"]");
      var elements = [];

      if (!matchElement) {
        elements = toArray(querySelector(selector));
      }

      if (matchElement && matchElement.matches(selector)) {
        elements = [matchElement];
      }

      elements.forEach(function (element) {
        /* __vm_cb: whether the load callback has been called
         * __vm_l: set by onload attribute, whether the element was loaded
         * __vm_ev: whether the event listener was added or not
         */
        if (element.__vm_cb) {
          return;
        }

        var onload = function onload() {
          /* Mark that the callback for this element has already been called,
           * this prevents the callback to run twice in some (rare) conditions
           */
          element.__vm_cb = true;
          /* onload needs to be removed because we only need the
           * attribute after ssr and if we dont remove it the node
           * will fail isEqualNode on the client
           */

          removeAttribute(element, 'onload');
          callback(element);
        };
        /* IE9 doesnt seem to load scripts synchronously,
         * causing a script sometimes/often already to be loaded
         * when we add the event listener below (thus adding an onload event
         * listener has no use because it will never be triggered).
         * Therefore we add the onload attribute during ssr, and
         * check here if it was already loaded or not
         */


        if (element.__vm_l) {
          onload();
          return;
        }

        if (!element.__vm_ev) {
          element.__vm_ev = true;
          element.addEventListener('load', onload);
        }
      });
    });
  }

  // instead of adding it to the html

  var attributeMap = {};
  /**
   * Updates the document's html tag attributes
   *
   * @param  {Object} attrs - the new document html attributes
   * @param  {HTMLElement} tag - the HTMLElement tag to update with new attrs
   */

  function updateAttribute(appId, options, type, attrs, tag) {
    var _ref = options || {},
        attribute = _ref.attribute;

    var vueMetaAttrString = tag.getAttribute(attribute);

    if (vueMetaAttrString) {
      attributeMap[type] = JSON.parse(decodeURI(vueMetaAttrString));
      removeAttribute(tag, attribute);
    }

    var data = attributeMap[type] || {};
    var toUpdate = []; // remove attributes from the map
    // which have been removed for this appId

    for (var attr in data) {
      if (data[attr] !== undefined && appId in data[attr]) {
        toUpdate.push(attr);

        if (!attrs[attr]) {
          delete data[attr][appId];
        }
      }
    }

    for (var _attr in attrs) {
      var attrData = data[_attr];

      if (!attrData || attrData[appId] !== attrs[_attr]) {
        toUpdate.push(_attr);

        if (attrs[_attr] !== undefined) {
          data[_attr] = data[_attr] || {};
          data[_attr][appId] = attrs[_attr];
        }
      }
    }

    for (var _i = 0, _toUpdate = toUpdate; _i < _toUpdate.length; _i++) {
      var _attr2 = _toUpdate[_i];
      var _attrData = data[_attr2];
      var attrValues = [];

      for (var _appId in _attrData) {
        Array.prototype.push.apply(attrValues, [].concat(_attrData[_appId]));
      }

      if (attrValues.length) {
        var attrValue = includes(booleanHtmlAttributes, _attr2) && attrValues.some(Boolean) ? '' : attrValues.filter(function (v) {
          return v !== undefined;
        }).join(' ');
        tag.setAttribute(_attr2, attrValue);
      } else {
        removeAttribute(tag, _attr2);
      }
    }

    attributeMap[type] = data;
  }

  /**
   * Updates the document title
   *
   * @param  {String} title - the new title of the document
   */
  function updateTitle(title) {
    if (!title && title !== '') {
      return;
    }

    document.title = title;
  }

  /**
   * Updates meta tags inside <head> and <body> on the client. Borrowed from `react-helmet`:
   * https://github.com/nfl/react-helmet/blob/004d448f8de5f823d10f838b02317521180f34da/src/Helmet.js#L195-L245
   *
   * @param  {('meta'|'base'|'link'|'style'|'script'|'noscript')} type - the name of the tag
   * @param  {(Array<Object>|Object)} tags - an array of tag objects or a single object in case of base
   * @return {Object} - a representation of what tags changed
   */

  function updateTag(appId, options, type, tags, head, body) {
    var _ref = options || {},
        attribute = _ref.attribute,
        tagIDKeyName = _ref.tagIDKeyName;

    var dataAttributes = commonDataAttributes.slice();
    dataAttributes.push(tagIDKeyName);
    var newElements = [];
    var queryOptions = {
      appId: appId,
      attribute: attribute,
      type: type,
      tagIDKeyName: tagIDKeyName
    };
    var currentElements = {
      head: queryElements(head, queryOptions),
      pbody: queryElements(body, queryOptions, {
        pbody: true
      }),
      body: queryElements(body, queryOptions, {
        body: true
      })
    };

    if (tags.length > 1) {
      // remove duplicates that could have been found by merging tags
      // which include a mixin with metaInfo and that mixin is used
      // by multiple components on the same page
      var found = [];
      tags = tags.filter(function (x) {
        var k = JSON.stringify(x);
        var res = !includes(found, k);
        found.push(k);
        return res;
      });
    }

    tags.forEach(function (tag) {
      if (tag.skip) {
        return;
      }

      var newElement = document.createElement(type);

      if (!tag.once) {
        newElement.setAttribute(attribute, appId);
      }

      Object.keys(tag).forEach(function (attr) {
        /* istanbul ignore next */
        if (includes(tagProperties, attr)) {
          return;
        }

        if (attr === 'innerHTML') {
          newElement.innerHTML = tag.innerHTML;
          return;
        }

        if (attr === 'json') {
          newElement.innerHTML = JSON.stringify(tag.json);
          return;
        }

        if (attr === 'cssText') {
          if (newElement.styleSheet) {
            /* istanbul ignore next */
            newElement.styleSheet.cssText = tag.cssText;
          } else {
            newElement.appendChild(document.createTextNode(tag.cssText));
          }

          return;
        }

        if (attr === 'callback') {
          newElement.onload = function () {
            return tag[attr](newElement);
          };

          return;
        }

        var _attr = includes(dataAttributes, attr) ? "data-".concat(attr) : attr;

        var isBooleanAttribute = includes(booleanHtmlAttributes, attr);

        if (isBooleanAttribute && !tag[attr]) {
          return;
        }

        var value = isBooleanAttribute ? '' : tag[attr];
        newElement.setAttribute(_attr, value);
      });
      var oldElements = currentElements[getElementsKey(tag)]; // Remove a duplicate tag from domTagstoRemove, so it isn't cleared.

      var indexToDelete;
      var hasEqualElement = oldElements.some(function (existingTag, index) {
        indexToDelete = index;
        return newElement.isEqualNode(existingTag);
      });

      if (hasEqualElement && (indexToDelete || indexToDelete === 0)) {
        oldElements.splice(indexToDelete, 1);
      } else {
        newElements.push(newElement);
      }
    });
    var oldElements = [];

    for (var _type in currentElements) {
      Array.prototype.push.apply(oldElements, currentElements[_type]);
    } // remove old elements


    oldElements.forEach(function (element) {
      element.parentNode.removeChild(element);
    }); // insert new elements

    newElements.forEach(function (element) {
      if (element.hasAttribute('data-body')) {
        body.appendChild(element);
        return;
      }

      if (element.hasAttribute('data-pbody')) {
        body.insertBefore(element, body.firstChild);
        return;
      }

      head.appendChild(element);
    });
    return {
      oldTags: oldElements,
      newTags: newElements
    };
  }

  /**
   * Performs client-side updates when new meta info is received
   *
   * @param  {Object} newInfo - the meta info to update to
   */

  function updateClientMetaInfo(appId, options, newInfo) {
    options = options || {};
    var _options = options,
        ssrAttribute = _options.ssrAttribute,
        ssrAppId = _options.ssrAppId; // only cache tags for current update

    var tags = {};
    var htmlTag = getTag(tags, 'html'); // if this is a server render, then dont update

    if (appId === ssrAppId && htmlTag.hasAttribute(ssrAttribute)) {
      // remove the server render attribute so we can update on (next) changes
      removeAttribute(htmlTag, ssrAttribute); // add load callbacks if the

      var addLoadListeners = false;
      tagsSupportingOnload.forEach(function (type) {
        if (newInfo[type] && addCallbacks(options, type, newInfo[type])) {
          addLoadListeners = true;
        }
      });

      if (addLoadListeners) {
        addListeners();
      }

      return false;
    } // initialize tracked changes


    var tagsAdded = {};
    var tagsRemoved = {};

    for (var type in newInfo) {
      // ignore these
      if (includes(metaInfoOptionKeys, type)) {
        continue;
      }

      if (type === 'title') {
        // update the title
        updateTitle(newInfo.title);
        continue;
      }

      if (includes(metaInfoAttributeKeys, type)) {
        var tagName = type.substr(0, 4);
        updateAttribute(appId, options, type, newInfo[type], getTag(tags, tagName));
        continue;
      } // tags should always be an array, ignore if it isnt


      if (!isArray(newInfo[type])) {
        continue;
      }

      var _updateTag = updateTag(appId, options, type, newInfo[type], getTag(tags, 'head'), getTag(tags, 'body')),
          oldTags = _updateTag.oldTags,
          newTags = _updateTag.newTags;

      if (newTags.length) {
        tagsAdded[type] = newTags;
        tagsRemoved[type] = oldTags;
      }
    }

    return {
      tagsAdded: tagsAdded,
      tagsRemoved: tagsRemoved
    };
  }

  var appsMetaInfo;
  function addApp(rootVm, appId, options) {
    return {
      set: function set(metaInfo) {
        return setMetaInfo(rootVm, appId, options, metaInfo);
      },
      remove: function remove() {
        return removeMetaInfo(rootVm, appId, options);
      }
    };
  }
  function setMetaInfo(rootVm, appId, options, metaInfo) {
    // if a vm exists _and_ its mounted then immediately update
    if (rootVm && rootVm.$el) {
      return updateClientMetaInfo(appId, options, metaInfo);
    } // store for later, the info
    // will be set on the first refresh


    appsMetaInfo = appsMetaInfo || {};
    appsMetaInfo[appId] = metaInfo;
  }
  function removeMetaInfo(rootVm, appId, options) {
    if (rootVm && rootVm.$el) {
      var tags = {};

      var _iterator = _createForOfIteratorHelper(metaInfoAttributeKeys),
          _step;

      try {
        for (_iterator.s(); !(_step = _iterator.n()).done;) {
          var type = _step.value;
          var tagName = type.substr(0, 4);
          updateAttribute(appId, options, type, {}, getTag(tags, tagName));
        }
      } catch (err) {
        _iterator.e(err);
      } finally {
        _iterator.f();
      }

      return removeElementsByAppId(options, appId);
    }

    if (appsMetaInfo[appId]) {
      delete appsMetaInfo[appId];
      clearAppsMetaInfo();
    }
  }
  function getAppsMetaInfo() {
    return appsMetaInfo;
  }
  function clearAppsMetaInfo(force) {
    if (force || !Object.keys(appsMetaInfo).length) {
      appsMetaInfo = undefined;
    }
  }

  /**
   * Returns the correct meta info for the given component
   * (child components will overwrite parent meta info)
   *
   * @param  {Object} component - the Vue instance to get meta info from
   * @return {Object} - returned meta info
   */

  function getMetaInfo(options, info, escapeSequences, component) {
    options = options || {};
    escapeSequences = escapeSequences || [];
    var _options = options,
        tagIDKeyName = _options.tagIDKeyName; // Remove all "template" tags from meta
    // backup the title chunk in case user wants access to it

    if (info.title) {
      info.titleChunk = info.title;
    } // replace title with populated template


    if (info.titleTemplate && info.titleTemplate !== '%s') {
      applyTemplate({
        component: component,
        contentKeyName: 'title'
      }, info, info.titleTemplate, info.titleChunk || '');
    } // convert base tag to an array so it can be handled the same way
    // as the other tags


    if (info.base) {
      info.base = Object.keys(info.base).length ? [info.base] : [];
    }

    if (info.meta) {
      // remove meta items with duplicate vmid's
      info.meta = info.meta.filter(function (metaItem, index, arr) {
        var hasVmid = !!metaItem[tagIDKeyName];

        if (!hasVmid) {
          return true;
        }

        var isFirstItemForVmid = index === findIndex(arr, function (item) {
          return item[tagIDKeyName] === metaItem[tagIDKeyName];
        });
        return isFirstItemForVmid;
      }); // apply templates if needed

      info.meta.forEach(function (metaObject) {
        return applyTemplate(options, metaObject);
      });
    }

    return escapeMetaInfo(options, info, escapeSequences);
  }

  /**
   * When called, will update the current meta info with new meta info.
   * Useful when updating meta info as the result of an asynchronous
   * action that resolves after the initial render takes place.
   *
   * Credit to [Sébastien Chopin](https://github.com/Atinux) for the suggestion
   * to implement this method.
   *
   * @return {Object} - new meta info
   */

  function refresh(rootVm, options) {
    options = options || {}; // make sure vue-meta was initiated

    if (!rootVm[rootConfigKey]) {
      showWarningNotSupported();
      return {};
    } // collect & aggregate all metaInfo $options


    var rawInfo = getComponentMetaInfo(options, rootVm);
    var metaInfo = getMetaInfo(options, rawInfo, clientSequences, rootVm);
    var appId = rootVm[rootConfigKey].appId;
    var tags = updateClientMetaInfo(appId, options, metaInfo); // emit "event" with new info

    if (tags && isFunction(metaInfo.changed)) {
      metaInfo.changed(metaInfo, tags.tagsAdded, tags.tagsRemoved);
      tags = {
        addedTags: tags.tagsAdded,
        removedTags: tags.tagsRemoved
      };
    }

    var appsMetaInfo = getAppsMetaInfo();

    if (appsMetaInfo) {
      for (var additionalAppId in appsMetaInfo) {
        updateClientMetaInfo(additionalAppId, options, appsMetaInfo[additionalAppId]);
        delete appsMetaInfo[additionalAppId];
      }

      clearAppsMetaInfo(true);
    }

    return {
      vm: rootVm,
      metaInfo: metaInfo,
      // eslint-disable-line object-shorthand
      tags: tags
    };
  }

  function $meta(options) {
    options = options || {};
    /**
     * Returns an injector for server-side rendering.
     * @this {Object} - the Vue instance (a root component)
     * @return {Object} - injector
     */

    var $root = this.$root;
    return {
      getOptions: function getOptions$1() {
        return getOptions(options);
      },
      setOptions: function setOptions(newOptions) {
        var refreshNavKey = 'refreshOnceOnNavigation';

        if (newOptions && newOptions[refreshNavKey]) {
          options.refreshOnceOnNavigation = !!newOptions[refreshNavKey];
          addNavGuards($root);
        }

        var debounceWaitKey = 'debounceWait';

        if (newOptions && debounceWaitKey in newOptions) {
          var debounceWait = parseInt(newOptions[debounceWaitKey]);

          if (!isNaN(debounceWait)) {
            options.debounceWait = debounceWait;
          }
        }

        var waitOnDestroyedKey = 'waitOnDestroyed';

        if (newOptions && waitOnDestroyedKey in newOptions) {
          options.waitOnDestroyed = !!newOptions[waitOnDestroyedKey];
        }
      },
      refresh: function refresh$1() {
        return refresh($root, options);
      },
      inject: function inject(injectOptions) {
        return  showWarningNotSupportedInBrowserBundle('inject');
      },
      pause: function pause$1() {
        return pause($root);
      },
      resume: function resume$1() {
        return resume($root);
      },
      addApp: function addApp$1(appId) {
        return addApp($root, appId, options);
      }
    };
  }

  /**
   * Plugin install function.
   * @param {Function} Vue - the Vue constructor.
   */

  function install(Vue, options) {
    if (Vue.__vuemeta_installed) {
      return;
    }

    Vue.__vuemeta_installed = true;
    options = setOptions(options);

    Vue.prototype.$meta = function () {
      return $meta.call(this, options);
    };

    Vue.mixin(createMixin(Vue, options));
  }

  {
    // automatic install
    if (!isUndefined(window) && !isUndefined(window.Vue)) {
      /* istanbul ignore next */
      install(window.Vue);
    }
  }

  var index = {
    version: version,
    install: install,
    generate: function generate(metaInfo, options) {
      return  showWarningNotSupportedInBrowserBundle('generate');
    },
    hasMetaInfo: hasMetaInfo
  };

  return index;

})));