# `assess-reactive` — streaming assessment with debounce + cancel

## Purpose

Debounce + cancel-on-newer-input wrapper around `assess` for UI strength
meters that update as the user types. Each new input cancels the pending
assessment for the previous input; only the latest stable value reaches
the consumer. The wrapper honours an optional `AbortSignal` so callers
can tear down a meter without orphaning pending work.

## Features

- Configurable `debounceMs` (default 150 ms, range `[0, 5000]`)
- Cancel-on-newer-input — superseded inputs do not yield results
- Clean `AbortSignal` completion (no thrown error on abort)
- 200-character DoS guard surfaced as `INPUT_TOO_LONG`
- Backed by an `AsyncIterable<StrengthResult>` so consumers integrate via
  `for await`

## Usage: Basic Example

```ts
import { assessReactive } from "@suaveplan/password-strength";

async function* keystrokes() {
 yield "p";
 yield "pa";
 yield "pas";
 yield "pass";
}

for await (const r of assessReactive(keystrokes())) {
 console.log(r.password, r.score);
}
```

## Usage: Advanced Example

```ts
import { assessReactive } from "@suaveplan/password-strength";

const controller = new AbortController();
const stream = assessReactive(keystrokes(), {
 debounceMs: 100,
 signal: controller.signal,
 assessOptions: { userInputs: ["alice@example.com"] },
});

setTimeout(() => controller.abort(), 50);

for await (const r of stream) {
 console.log(r.score);
}
```

## API Reference

- `assessReactive(input$: AsyncIterable<string>, opts?: AssessReactiveOptions): AsyncIterable<StrengthResult>`
  - Throws `PasswordStrengthError(PWSTRENGTH.INVALID_OPTIONS)` on schema
    failure; throws `PasswordStrengthError(PWSTRENGTH.INPUT_TOO_LONG)` when
    an input exceeds 200 characters.
- `AssessReactiveOptions`: `{ debounceMs?, signal?, assessOptions? }`.

## Implementation Notes

The wrapper schedules each input via `setTimeout(debounceMs)`. A newer
input cancels the pending timer and reschedules. Consumers awaiting the
next iteration are tracked in an internal resolver queue; an emitted
result settles the next resolver or buffers if none is waiting. Abort
clears the pending timer and resolves every waiting consumer with
`{ done: true }`; the iterable then completes cleanly without throwing.
The `ABORTED` error code is registered with the OTel counter on abort so
operators can monitor cancellation rates without inspecting the iterator
itself.