# Register Default Strategies — Schema

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_(no submodules)_
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## Purpose

Zod schema for the `manager` argument of `registerDefaultStrategies`. Validates that an external caller hands the function a real `PackingStrategyManager` instance (not a plain object that "quacks like" one) so the chain ordering invariants the function depends on are guaranteed at the boundary. Identity is preserved — the parsed value is the same instance the caller passed in, so `registerDefaultStrategies(manager)` mutates the caller's manager rather than a clone.

This package's strategy classes are themselves parameterless and therefore expose no per-strategy options to validate. The single boundary that needs a schema is `registerDefaultStrategies(manager)`. Strategy *shape* (`canHandle`/`pack`/`unpack` are functions) is already validated upstream by `packingStrategySchema` in `@suaveplan/bitpacker`.

## Features

- `packingStrategyManagerSchema` — `z.custom<PackingStrategyManager>` `instanceof` check
- Identity preservation (no wrapping)
- Rejects null, undefined, and plain objects that share the manager API surface

## Usage: Basic Example

```ts
import {
    PackingStrategyManager,
    BitPackerError,
    BITPACKER_CODES,
} from "@suaveplan/bitpacker";
import {
    packingStrategyManagerSchema,
    registerDefaultStrategies,
} from "@suaveplan/bitpacker-strategies";

const manager = packingStrategyManagerSchema.parse(new PackingStrategyManager());
registerDefaultStrategies(manager);
```

## Usage: Advanced Example

```ts
import {
    PackingStrategyManager,
    BitPackerError,
    BITPACKER_CODES,
} from "@suaveplan/bitpacker";
import {
    packingStrategyManagerSchema,
    registerDefaultStrategies,
} from "@suaveplan/bitpacker-strategies";

function bootstrap(rawManager: unknown): PackingStrategyManager {
    const result = packingStrategyManagerSchema.safeParse(rawManager);
    if (!result.success) {
        throw new BitPackerError(
            BITPACKER_CODES.INVALID_SCHEMA,
            "registerDefaultStrategies received a non-manager value",
            { cause: result.error }
        );
    }
    registerDefaultStrategies(result.data);
    return result.data;
}
```

## API Reference

### `packingStrategyManagerSchema: z.ZodType<PackingStrategyManager>`

Strict `instanceof` validator. Returns the input value unchanged on success; throws `ZodError` with the message `"manager must be a PackingStrategyManager instance"` on failure.

## Implementation Notes

- **No per-strategy schemas.** Every shipped strategy in this package is parameterless — `new ArrayPackingStrategy()`, `new ObjectPackingStrategy()`, etc. There is nothing per-strategy to validate at construction time. Strategy shape (`canHandle`/`pack`/`unpack`) is enforced by `packingStrategySchema` in `@suaveplan/bitpacker` at the registration boundary, so this package does not duplicate that validation.
- **`instanceof` over duck-typing.** A plain object with `add`/`register` methods would compile, but the order-sensitive insertion logic in `PackingStrategyManager.register` (insert before catch-all) depends on the class internals. Refusing duck-types prevents subtle ordering bugs that would only surface deep into a pack/unpack chain.