[RN] Refactor getting the default URL

Move it away from AbstractApp into an auxiliary function. In addition, introduce
a new `getServerURL` function which gets the configured server URL and defaults
to meet.jit.si as before.

react/features/app/actions.js

 import { setFatalError } from '../overlay';
 
 import { APP_WILL_MOUNT, APP_WILL_UNMOUNT } from './actionTypes';
+import { getDefaultURL } from './functions';
 
 const logger = require('jitsi-meet-logger').getLogger(__filename);
 
     // If the specified location (URI) does not identify a host, use the app's
     // default.
     if (!location || !location.host) {
-        const defaultLocation
-            = parseURIString(getState()['features/app'].app._getDefaultURL());
+        const defaultLocation = parseURIString(getDefaultURL(getState));
 
         if (location) {
             location.host = defaultLocation.host;

react/features/app/components/AbstractApp.js

 import { OverlayContainer } from '../../overlay';
 
 import { appNavigate, appWillMount, appWillUnmount } from '../actions';
-
-/**
- * The default URL to open if no other was specified to {@code AbstractApp} via
- * props.
- *
- * FIXME: This is not at the best place here. This should be either in the
- * base/settings feature or a default in base/config.
- */
-const DEFAULT_URL = 'https://meet.jit.si';
+import { getDefaultURL } from '../functions';
 
 /**
  * Base (abstract) class for main App component.
      * mounts.
      */
     _getDefaultURL() {
-        // If the execution environment provides a Location abstraction, then
-        // this App at already at that location but it must be made aware of the
-        // fact.
-        const windowLocation = this.getWindowLocation();
-
-        if (windowLocation) {
-            const href = windowLocation.toString();
-
-            if (href) {
-                return href;
-            }
-        }
-
-        return (
-            this.props.defaultURL
-                || this.state.store.getState()['features/base/settings']
-                    .serverURL
-                || DEFAULT_URL);
+        return getDefaultURL(this.state.store);
     }
 
     /**

react/features/app/functions.any.js

 // @flow
 
 import { toState } from '../base/redux';
+import { getServerURL } from '../base/settings';
 
 /**
  * Gets the value of a specific React {@code Component} prop of the currently
 
     return undefined;
 }
+
+/**
+ * Retrieves the default URL for the app. This can either come from a prop to
+ * the root App component or be configured in the settings.
+ *
+ * @param {Function|Object} stateful - The redux store or {@code getState}
+ * function.
+ * @returns {string} - Default URL for the app.
+ */
+export function getDefaultURL(stateful: Function | Object) {
+    const state = toState(stateful);
+    const { app } = state['features/app'];
+
+    // If the execution environment provides a Location abstraction (e.g. a Web
+    // browser), then we'll presume it's the one and only base URL it can be on.
+    const windowLocation = app.getWindowLocation();
+
+    if (windowLocation) {
+        const href = windowLocation.toString();
+
+        if (href) {
+            return href;
+        }
+    }
+
+    return getAppProp(state, 'defaultURL') || getServerURL(state);
+}

react/features/base/known-domains/middleware.js

 // @flow
 
-import { APP_WILL_MOUNT } from '../../app';
+import { APP_WILL_MOUNT, getDefaultURL } from '../../app';
+
 import { SET_ROOM } from '../conference';
 import { MiddlewareRegistry } from '../redux';
 import { parseURIString } from '../util';
  * @returns {Promise}
  */
 function _appWillMount({ dispatch, getState }) {
-    const defaultURL
-        = parseURIString(getState()['features/app'].app._getDefaultURL());
+    const defaultURL = parseURIString(getDefaultURL(getState));
 
     dispatch(addKnownDomains(defaultURL.host));
 }

react/features/base/settings/constants.js

+// @flow
+
+/**
+ * The default server URL to open if no other was specified.
+ */
+export const DEFAULT_SERVER_URL = 'https://meet.jit.si';

react/features/base/settings/functions.js

 import { parseURLParams } from '../config';
 import { toState } from '../redux';
 
+import { DEFAULT_SERVER_URL } from './constants';
 
 /**
  * Returns the effective value of a configuration/preference/setting by applying
 
     return undefined;
 }
+
+/**
+ * Gets the currently configured server URL.
+ *
+ * @param {Object|Function} stateful - The redux state object or
+ * {@code getState} function.
+ * @returns {string} - The currently configured server URL.
+ */
+export function getServerURL(stateful: Object | Function) {
+    const state = toState(stateful);
+
+    return state['features/base/settings'].serverURL || DEFAULT_SERVER_URL;
+}

react/features/base/settings/index.js

 export * from './actions';
+export * from './constants';
 export * from './functions';
 
 import './middleware';

react/features/recent-list/components/RecentList.native.js

 import React, { Component } from 'react';
 import { connect } from 'react-redux';
 
-import { appNavigate } from '../../app';
+import { appNavigate, getDefaultURL } from '../../app';
 import {
     getLocalizedDateFormatter,
     getLocalizedDurationFormatter,
  */
 export function _mapStateToProps(state: Object) {
     return {
-        _defaultServerURL: state['features/app'].app._getDefaultURL(),
+        _defaultServerURL: getDefaultURL(state),
         _recentList: state['features/recent-list']
     };
 }

react/features/settings/components/AbstractSettingsView.js

 
 import { Component } from 'react';
 
+import { getDefaultURL } from '../../app';
 import { updateSettings } from '../../base/settings';
 
 /**
  */
 export function _mapStateToProps(state: Object) {
     return {
-        _serverURL: state['features/app'].app._getDefaultURL(),
+        _serverURL: getDefaultURL(state),
         _settings: state['features/base/settings'],
         _visible: state['features/settings'].visible
     };