# trans-form-middleware — Design (Q1–Q61)

Status: **implementation scaffold** (v0.1.0)

Companion package: `@windychen/trans-form-component` (Vue 3 dynamic query form).

## Role

Receive component filter output → structured `{ field, query, op, value, logic?, values?, empty? }[]`. **No SQL generation.**

## Key decisions

| # | Decision |
|---|----------|
| 1–2 | Node.js pure JS; structured filters only |
| 8 | Dual fields: `query` (code) + `op` (symbol) |
| 14 | `mode`: pass-through (default) / flat / tree |
| 24–25 | Zero deps; ESM only; no bundling (`src/index.js`) |
| 38 | `empty: true` preserved by default |
| 39 | Built-in `DEFAULT_OPERATOR_MAP`, merge via `operatorMap` |
| 41 | Multi-function exports: `parseFilters`, `toTree`, `mapOperators`, … |
| 44 | `strict` default false |
| 46 | Multi-value: `value` (string) + `values` (parsed array) |
| 49–50 | `allowedFields` required; `unknownField: 'error'` default |
| 60 | Component emits all state flags; middleware skips `disabled` by default |
| 61 | Also skips `hidden`; `skipEmpty` option controls empty items |

## Output example

```json
[
  {
    "field": "tags",
    "query": "IN",
    "op": "IN",
    "value": "a,b,c",
    "values": ["a", "b", "c"],
    "logic": "OR"
  }
]
```

## Operator map

`EQ→=`, `NE→<>`, `GT→>`, `GTE→>=`, `LT→<`, `LTE→<=`, `LIKE→LIKE`, `IN→IN`, `NOT_IN→NOT IN`, `BETWEEN→BETWEEN`, `IS_NULL→IS NULL`, `IS_NOT_NULL→IS NOT NULL`

## CI

Copy of windychen-utils pattern: commit message must contain `chore` + `版本` + `更新` to trigger publish.