@mmmnt/feat-adapter-playwright

Response adapter for Feat where a command is a real browser journey. Each command routes to a journey module you author: it receives a Playwright Page, drives the flow, and returns the normalized outcome predictions match against. The spec doesn't change — when: CheckoutWithCard {…} reads the same whether the stimulus is an HTTP call or a full browser checkout.

// feat.config.json
"response": {
  "adapter": "@mmmnt/feat-adapter-playwright",
  "invoke": { "baseUrlEnv": "FEAT_E2E_BASE_URL", "browser": "chromium", "headless": true },
  "commands": {
    "CheckoutWithCard": { "module": "journeys/checkout.mjs", "export": "checkoutWithCard" }
  },
  "actors": { "buyer": { "storageState": "playwright/.auth/buyer.json" } }
}

// journeys/checkout.mjs
export async function checkoutWithCard(page, payload, ctx) {
  await page.goto(`${ctx.baseUrl}/checkout`);
  await page.fill("#plan", payload.plan);
  await page.click("#pay");
  await page.waitForSelector("#confirmation");
  return { status: 200, body: { orderId: await page.textContent("#order-id") } };
}

Journey contract: (page, payload, ctx) => Promise<{ status, body }> with ctx = { baseUrl, actor }. invoke.baseUrl is a literal; invoke.baseUrlEnv names the environment variable carrying it (mutually exclusive, unset = loud failure) — the same contract as feat-adapter-http, keeping configs per-tier while origins belong to the environment. Actors map to Playwright storageState files (pre-authenticated sessions); anonymous gets a fresh context. Each invoke runs in its own browser context; a configurable timeout (default 30s) fails hung journeys. playwright is a peer dependency — your project provides it.

Pair with service adapters (filesystem, Stripe, …) to predict the full footprint of a user journey, not just what the browser shows.

Part of Feature — the .feat execution specification language. Docs: https://github.com/mmmnt/feature/wiki

MIT