---
title: "@unikvs/allow-repair"
description: "Middleware that controls whether read-time repair writes are allowed."
---

## Overview [#overview]

`@unikvs/allow-repair` is a plugin that allows or denies read-time repair writes.Middleware

It extends `PassThrough` and passes data through without conversion. Use it to temporarily stop repair writes to earlier storages in a multi-storage setup.

- `name` is `AllowRepair`.
- `isOpen` is always `true`. `open()` is unnecessary.
- Repair is allowed initially. `disable()` switches to denying.

Install with:

```package-install
npm install @unikvs/allow-repair
```

## Usage [#usage]

`AllowRepair` implements IMiddleware. Pass it to UniKvs with use().

```ts
import { AllowRepair } from "@unikvs/allow-repair";
```

The following reads with repair denied, then re-reads after allowing it:

```ts
import { AllowRepair } from "@unikvs/allow-repair";
import { Memory } from "@unikvs/memory";
import * as unikvs from "unikvs";

const gate = new AllowRepair();
const kvs = new unikvs.Builder<{ foo: unikvs.Value<Uint8Array> }>()
  .use(gate)
  .persist(new Memory())
  .build();

await kvs.open();
await kvs.set("foo", new Uint8Array([0, 1, 2]));

gate.disable();

try {
  await kvs.get("foo", { repair: true });
} catch {
  console.log("repair was denied");
}

gate.enable();

const bytes = await kvs.get("foo", { repair: true });
console.log(bytes); // Uint8Array(3) [0, 1, 2]

await kvs.close();
```

## Data types [#data-types]

| Method         | Input    | Output   |
| -------------- | -------- | -------- |
| `encode`       | `TData`  | `TData`  |
| `decode`       | `TData`  | `TData`  |
| `encodeStream` | `TChunk` | `TChunk` |
| `decodeStream` | `TChunk` | `TChunk` |

- `encode` outputs the input data unchanged.
- `decode` outputs the input data unchanged.
- `encodeStream` outputs the input stream unchanged.
- `decodeStream` outputs the input stream unchanged.
- `use` only decides repair eligibility for `get` and `stream`; it never changes data.

## Errors [#errors]

This package has no package-specific errors.

`use()` throws [`RepairNotAllowedError`](/unikvs/en/packages/core/errors#error-repair-not-allowed) when repair is denied. It never throws when `enabled` is `true` or when the read has repair disabled.