The filter descriptors support accessor functions in the "field" option. It would be great to see this implemented in the sort, group, and aggregate options.

const result = process(items, {
    filter: {
        logic: "and",
        filters: [{ field: x => x.getValue(), operator: "eq", value: 0 }], // <- supported
    },
    group: [
        field: x => x.getValue(), // <- not supported
        aggregates: [{ aggregate: "sum", field: x => x.getValue() }] // <- not supported
    ],
    sort: [{ field: x => x.getValue(), dir: "desc" }] // <- not supported
});