discourse/app/assets/javascripts/discourse/models/nav-item.js.es6

import { toTitleCase } from 'discourse/lib/formatter';
import computed from 'ember-addons/ember-computed-decorators';

const NavItem = Discourse.Model.extend({

  @computed("categoryName", "name")
  title(categoryName, name) {
    const extra = {};

    if (categoryName) {
      name = "category";
      extra.categoryName = categoryName;
    }

    return I18n.t("filters." + name.replace("/", ".") + ".help", extra);
  },

  @computed("categoryName", "name", "count")
  displayName(categoryName, name, count) {
    count = count || 0;

    if (name === 'latest' && !Discourse.Site.currentProp('mobileView')) {
      count = 0;
    }

    let extra = { count: count };
    const titleKey = count === 0 ? '.title' : '.title_with_count';

    if (categoryName) {
      name = 'category';
      extra.categoryName = toTitleCase(categoryName);
    }

    return I18n.t(`filters.${name.replace("/", ".") + titleKey}`, extra);
  },

  @computed("name")
  categoryName(name) {
    const split = name.split('/');
    return split[0] === 'category' ? split[1] : null;
  },

  @computed("name")
  categorySlug(name) {
    const split = name.split('/');
    if (split[0] === 'category' && split[1]) {
      const cat = Discourse.Site.current().categories.findBy('nameLower', split[1].toLowerCase());
      return cat ? Discourse.Category.slugFor(cat) : null;
    }
    return null;
  },

  @computed("filterMode")
  href(filterMode) {
    let customHref = null;

    _.each(NavItem.customNavItemHrefs, function(cb) {
      customHref = cb.call(this, this);
      if (customHref) { return false; }
    }, this);

    if (customHref) { return customHref; }

    return Discourse.getURL("/") + filterMode;
  },

  @computed("name", "category", "categorySlug", "noSubcategories")
  filterMode(name, category, categorySlug, noSubcategories) {
    if (name.split('/')[0] === 'category') {
      return 'c/' + categorySlug;
    } else {
      let mode = "";
      if (category) {
        mode += "c/";
        mode += Discourse.Category.slugFor(category);
        if (noSubcategories) { mode += '/none'; }
        mode += "/l/";
      }
      return mode + name.replace(' ', '-');
    }
  },

  @computed("name", "category", "topicTrackingState.messageCount")
  count(name, category) {
    const state = this.get("topicTrackingState");
    if (state) {
      return state.lookupCount(name, category);
    }
  }

});

 const ExtraNavItem = NavItem.extend({
  @computed("href")
  href: (href) => href
});

NavItem.reopenClass({

  extraArgsCallbacks: [],
  customNavItemHrefs: [],
  extraNavItems: [],

  // create a nav item from the text, will return null if there is not valid nav item for this particular text
  fromText(text, opts) {
    var split = text.split(","),
        name = split[0],
        testName = name.split("/")[0],
        anonymous = !Discourse.User.current();

    opts = opts || {};

    if (anonymous && !Discourse.Site.currentProp('anonymous_top_menu_items').includes(testName)) return null;

    if (!Discourse.Category.list() && testName === "categories") return null;
    if (!Discourse.Site.currentProp('top_menu_items').includes(testName)) return null;

    var args = { name: name, hasIcon: name === "unread" }, extra = null, self = this;
    if (opts.category) { args.category = opts.category; }
    if (opts.noSubcategories) { args.noSubcategories = true; }
    _.each(NavItem.extraArgsCallbacks, function(cb) {
      extra = cb.call(self, text, opts);
      _.merge(args, extra);
    });

    const store = Discourse.__container__.lookup('service:store');
    return store.createRecord('nav-item', args);
  },

  buildList(category, args) {
    args = args || {};

    if (category) { args.category = category; }

    let items = Discourse.SiteSettings.top_menu.split("|");

    if (args.filterMode && !_.some(items, i => i.indexOf(args.filterMode) !== -1)) {
      items.push(args.filterMode);
    }

    items = items.map(i => Discourse.NavItem.fromText(i, args))
                 .filter(i => i !== null && !(category && i.get("name").indexOf("categor") === 0));

    return items.concat(NavItem.extraNavItems);
  }

});

export default NavItem;

export function extraNavItemProperties(cb) {
  NavItem.extraArgsCallbacks.push(cb);
}

export function customNavItemHref(cb) {
  NavItem.customNavItemHrefs.push(cb);
}

export function addNavItem(item) {
  NavItem.extraNavItems.push(ExtraNavItem.create(item));
}