# API: hyper-p2p-fulltext-lite

**Export:** `{ HyperP2PFulltextLite, PROTOCOL }`  
**Protocol:** `fulltext-lite/v1` (identifier only — **no P2P wire messages**)

## Overview

`HyperP2PFulltextLite` is an in-memory inverted index for short documents. It tokenizes text (lowercase, alphanumeric tokens, stop-word removal), maintains term → document ID sets, and runs **AND** queries across query terms with a simple term-hit score.

The module is **local-only**: no Hyperswarm, no gossip. Suitable for Pear/Bare apps that need lightweight full-text search without external search engines.

## Constructor

```js
const { HyperP2PFulltextLite } = require('hyper-p2p-fulltext-lite')
const ft = new HyperP2PFulltextLite()
```

No constructor options. State: `_docs` (id → entry), `_index` (term → Set of doc ids), `_stats`.

## Stop words

Built-in set: `a`, `an`, `the`, `and`, `or`, `of`, `to`, `in`, `on`, `for`, `is` (tokens length ≤ 1 also dropped).

## Methods

### `tokenize(text)`

- **Returns:** `string[]` of normalized tokens
- **Null/undefined text:** `[]`

### `addDocument(id, text)`

- **Parameters:** `id` (non-empty), `text` (any, coerced to string)
- **Returns:** `{ id, text, tokens, at }`
- **Behavior:** Removes prior posting lists for `id` if re-indexing; updates inverted index; emits `document`
- **Increments:** `stats.indexed`

### `search(query)`

- **Returns:** sorted array `{ id, score, snippet }` where `snippet` is first 120 chars of document text
- **Scoring:** count of query terms present in document tokens
- **Empty tokenized query:** `[]`
- **Logic:** intersection of per-term document sets (AND)
- **Increments:** `stats.queries`

### `getDocument(id)`

Returns stored entry or `null`.

### `removeDocument(id)`

Removes postings and document. Returns `true` if existed.

### `listDocuments()`

Returns all document entries as an array.

### `getStats()`

```js
{ indexed, queries, documents, terms, protocol }
```

### `ready()` / `close()`

`ready()` resolves immediately. `close()` clears maps and emits `closed`.

## Events

| Event | Payload |
|-------|---------|
| `document` | `{ id, text, tokens, at }` |
| `closed` | — |

## Wire messages

None. `PROTOCOL` is exported for registry consistency only.

## Errors

`assertNonEmpty` on `addDocument` and `removeDocument` for empty `id`.

## Design limits

- No stemming, no phrase queries, no OR mode
- Re-indexing a document rewrites all its term postings
- Memory scales with total tokens across documents

## Example

```js
const ft = new HyperP2PFulltextLite()
ft.addDocument('doc-1', 'hyper p2p fulltext search')
console.log(ft.search('p2p search'))
await ft.close()
```

## Testing

```bash
npm install && npm test
```