# Wire format


A `Decimal` must never serialize as a JSON number — that would hand the value
to the binary float parser and destroy precision at the boundary. The library
provides three explicit serializations:

| Function | Output | Use |
|----------|--------|-----|
| `toPG(d)` | `"12.34"` (plain string) | PostgreSQL `numeric` parameters — the DAL uses this |
| `toWire(d)` / `toJSON(d)` | `"12.34d"` (self-describing) | JSON APIs, Ext-JSON — the `d` suffix marks it for rehydration |
| `toString(d)` | `"12.34"` | display / logs |
| `toNumber(d)` | `number` — **lossy** | last-resort interop only |

## In JSON

```ts
JSON.stringify({ total });     // {"total":"73.47d"} — via toJSON
```

The `d`-suffixed string survives `JSON.parse` untouched and schema-aware
hydration (e.g. the SDK Ext-JSON middleware or the DAL hydration path) revives
it into a `Decimal` — precision never crosses a float.

## Hydration

- `fromWire("12.34d")` — parses the self-describing form (accepts plain `"12.34"` too)
- `fromPG("12.34")` — parses a `numeric` value as returned by PostgreSQL
- `parseDecimal` / `dec` — general entry point (`DecimalInput`)

`NaN`, `Infinity`, `-Infinity` (legal `numeric` values in PG ≥ 14) cannot be
represented — `fromPG`/`dec` throw `DecimalError` with `code: "NON_FINITE"`.
This is deliberate: a `Decimal` is always finite.