While working with LLD, I discovered another place that requires javascript preprocessing, but feels like it should be simpler: Preprocessing of individual discoveries.

Currently there is no way to do this but reading the whole JSON by javascript, making changes to individual discoveries and then re-exporting to JSON.

Currently the "LLD Macros" tab is fixed to one preprocessing command: JSONPath from individual discovery's sub-JSON - let's call it {#LLDVALUE}.

I propose expading this into a full per-individual-discovery preprocessing stage, adding other steps known from standard preprocessing, allowing more freedom in input formats.

I propose expanding the "LLD Macros" tab into this format:

By default include the, now implicit, "JSON to macros" step: