The ChangeWebMap Widget for ArcGIS Web AppBuilder allows users to switch the map content to another web map.
Using the Widget
Public Content Tab
The Public Content tab lists the web maps that are accessible to every one. When configuring the ChangeWebMap widget, the site administrator can filter the list of available web maps to a particular group or type.
My Content Tab
The My Content tab lists the web maps that are accessible to the current user. The first time the tab is displayed, you will need to sign into your Portal account.
Once logged in, the web maps accessible to your account will be displayed in the My Content tab.
Changing the Web Map
To change the map contents to another web map, click the web map in the list.
You will be prompted to Zoom In.
Choose No to keep the current map extents or Yes to zoom to the extents of the new web map.
Click the More Details link to open a browser window to the information page for the web map.
Source code and installation instructions may be found at GitHub - softwhere/ChangeWebMap-Widget
Thanks to the City of Garland, Texas for sponsoring the initial development of the ChangeWebMap Widget and releasing it to the community.