This function is an important part of how WebApp Layouts can automatically adapt to handle different sources of data.
It takes in a headings object which stores field IDs as keys next to the names of available field slots as values. It then returns a new object using the values in this
which stores the data values against those field slots so that the layout can output the data.
If you add a new field to the WebApp after creating the layout with SiteBuilder, you can safely access that value via the this
object as you normally would in a layout.
However, if you wish, you can also modify the existing headings in the JSON object.
Starting with this Object...
You could change it so that existing {{field_map['Title']}}
outputs would output values from a different field like so:
Or you can add a brand new slot to the WebApp {{field_map['Extra Slot']}}
and populate it with a new field's data:
As the field_headings are passed into the function, the function will return an object where the required data values are stored against the correct keys.