Ability to remove map fields which are empty about qewd-transform-json

[robtweed]

Use this (recently added and not yet documented) syntax:

"abc": "{<code>}"

This means: replace with the value in the code property of the data source object if it exists. If the code property doesn't exist in the data source object, remove the abc property from the result object

[robtweed]

Another trick is within a function transform, return this to delete the result object:

"<!delete>"

[aimythgit]

"abc": "{<code>}".
This feature did what was required.
Documenting for a better view
Instead of
"phone": "{{phone}}".
This would create an empty phone node if the phone is null or not found in the original document to transform.
Do
"phone": "{<phone>}"

[aimythgit]

This needs to have another enhancement.

what is needed is a hybrid solution.
Lets assume there are two fields in the incoming data

given_name
family_name

The mapping changes given_name to firstName and family_name to lastName.

If we do
firstName: "{<given_name>}"
lastName: "{<family_name>}"

If the given_name is empty or null the map won't copy. The issue here is if we do change first_name once with a non null value and then if we want to remove this. The map would not allow the null value to be entered.

So this feature needs to be enhanced to the following
if a field is found in the input then the map should take it. If the field does have a null value then the map should put back the null value.

E.g
"given_name": "Mary"

next we give
"given_name": null
Here the expectation is the mapping should give "firstName": null. Currently it's removing this field as it treats a field with null value and a field not present as same.

if only data has only that field
"family_name": "Jane"

The mapping should only give
"lastName" : "Jane". Here it can removing firstName field correctly.