SharePoint JSOM queries

Accessing SharePoint through JSOM is a very flexible and intuitive way of working with SharePoint.

Its advantages are:

1. Data can be accessed from any browser, in any application.
2. Javascript can be modified easily, and hence shorter deployment cycles.
3. Can be easily embedded in SharePoint hosted apps or even a content query webpart, providing vital ability to customize sharepoint OOB elements (such as menus, styles, links, etc.) without a lot of overhead of development, testing and deployment.

To get started with JSOM the following articles are a great read.

https://docs.microsoft.com/en-us/sharepoint/dev/sp-add-ins/complete-basic-operations-using-javascript-library-code-in-sharepoint

https://www.sharepointsky.com/jsom-sharepoint/

https://www.codeproject.com/Articles/841321/How-to-initialize-the-SharePoint-Client-Context-in

https://docs.microsoft.com/en-us/sharepoint/dev/spfx/web-parts/guidance/connect-to-sharepoint-using-jsom