Filtering values

For JSON source topics, the optional topic value mapping clause can be used to extract part of the source value.
A topic value mapping begins with the keyword as and is followed by a value directive.
This allows you to filter the values presented through reference topics.

Example

A value directive is delimited by angle brackets (<, >). It consists of the value keywords and a single JSON pointer parameter.
The JSON pointer selects the part of the source value to copy.

For example, given a source value of:

and the value mapping clause as <value(/balance)>, the reference topic value will be:

Topic value mappings are often used with path value mappings. For example: