# a-json (adapter system)

JSON transformation capability pack: 23 structural transforms — camelCase keys, flatten, dedupe, group-by, filter, pluck, merge-with-defaults, path extraction, computed fields, conditional routing...


JSON transformation **capability pack**. Ported from `leumas-middleware/lib/a.json` — the pure core:
23 structural transforms. Stripped: express `server.js`, `frontend/`, `public/`, `scripts/`, and the
infra helpers (`adapterRegistry.js`, `runAdapter.js`) that dynamically scanned the on-disk adapters
folder.

The **real helper functions** are reused verbatim under [`./helpers`](./helpers), and each source
adapter is preserved under [`./adapters/<name>/index.js`](./adapters) (import paths rewritten to the
co-located helpers). `index.js` imports each adapter's default export and exposes
`adapters[<id>] = (args) => <adapter>(args)`.

## Tools (`adapters`)

| tool | args | result |
|------|------|--------|
| `camelCaseKeys` | object/array | keys recased to camelCase |
| `flattenNested` | nested object | dot-path-flattened object |
| `dedupeByKey` | `array` or `{ data, key, strategy }` | de-duplicated array |
| `groupByKey` | `{ data, key }` | `{ <keyValue>: [...] }` |
| `filterByValue` | `{ data, key, value }` | filtered array |
| `pluckKeys` | `{ data, keysToPluck }` | projected array |
| `mergeWithDefaults` | `{ defaults, data }` | deep-merged object |
| `pathExtractor` | `{ data, paths }` | extracted values |
| `computedFields` | `{ data, computed }` | enriched rows |
| `conditionalRouter` | `{ data, rules }` | routed payload |
| `currencyNormalizer` / `temporalNormalizer` | `{ data, ... }` | normalized rows |
| `geoEnricher` / `graphBuilder` | `{ data, ... }` | enriched/graph output |
| `secretScrubber` | `{ data, keys }` | scrubbed payload |
| `schemaComparator` | `{ left, right }` | schema diff |
| `validationHarness` | `{ data, rules }` | validation report |
| `sortAndPaginate` | `{ data, options }` | page slice |
| `eventAccumulator` | `{ data, groupBy, metrics }` | aggregates |
| `referenceResolver` | `{ data, lookup, ... }` | resolved refs |
| `binaryEncoder` | `{ data, fields, format }` | encoded fields |
| `aiPrompt` | `{ data, template }` | built prompt |
| `textAnalyzer` | `{ data, field }` | text stats |

(`cloned_adapter` in the source was an exact duplicate of `camelCaseKeys` and was dropped.)


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Source: shared/engines/adapters/domain/a-json/README.md
Canonical: https://docs.leumas.tech/p/adapters/domain/a-json