What technology can be used today to build user defined user interfaces (little bit like salesforce)?

Salesforce has a very unique user interface. The users/customers can create / change page elements e.g. they need a button or they need text boxes, labels and the ui changes accordingly.

In essence it needs two core technology breakthroughs

1. defining a UI from database i.e. not have a statically defined page in html but generate the UI after reading corresponding database rows.
2. When the user interacts with the UI, the events need to be handled. Since the UI is dynamically defined, you cannot have client side javascript to handle it. So event handling for such dynamic pages should be server side.

Nodejs seems right choice as it provides unified language to code server side logic as well as client side events. I researched various technologies like react, angular, nodejs express etc. but none addresses either of these concerns.

Is there a mature technology that I can use for my application?

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