Adds a prefetch integration for near-instant page navigations (#3725)

* Adds a basic @astrojs/prefetch integration

* adding tests for custom selectors

* missed in last commit

* Adding a few docs, removing the option for `selectors` to be an element array

* adding an option for the concurrency limit

* fixing test for updated integration options

* Update packages/labs/prefetch/src/client.ts

Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>

* nit: removing the NodeJS.Timer type to allow typescript to infer the return

* updating docs for default selector with ~=

* Skip prefetching on 2G connections, or when data saver is enabled

* refactor: moving to packages/integrations, Astro Labs TBD down the road

* README typo fix

Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/packages/integrations/prefetch/playwright.config.js b/packages/integrations/prefetch/playwright.config.js
new file mode 100644
index 000000000..c8353201f
--- /dev/null
+++ b/packages/integrations/prefetch/playwright.config.js
@@ -0,0 +1,41 @@
+import { devices } from '@playwright/test';
+
+const config = {
+	testMatch: 'test/*.test.js',
+	/* Maximum time one test can run for. */
+	timeout: 30 * 1000,
+	expect: {
+		/**
+		 * Maximum time expect() should wait for the condition to be met.
+		 * For example in `await expect(locator).toHaveText();`
+		 */
+		timeout: 5000,
+	},
+	/* Fail the build on CI if you accidentally left test in the source code. */
+	forbidOnly: !!process.env.CI,
+	/* Retry on CI only */
+	retries: process.env.CI ? 5 : 0,
+	/* Opt out of parallel tests on CI. */
+	workers: 1,
+	/* Shared settings for all the projects below. See https://playwright.dev/docs/api/class-testoptions. */
+	use: {
+		/* Maximum time each action such as `click()` can take. Defaults to 0 (no limit). */
+		actionTimeout: 0,
+		/* Base URL to use in actions like `await page.goto('/')`. */
+		baseURL: process.env.PLAYWRIGHT_TEST_BASE_URL || 'http://localhost:3000',
+
+		/* Collect trace when retrying the failed test. See https://playwright.dev/docs/trace-viewer */
+		trace: 'on-first-retry',
+	},
+	projects: [
+		{
+			name: 'Chrome Stable',
+			use: {
+				browserName: 'chromium',
+				channel: 'chrome',
+			},
+		},
+	],
+};
+
+export default config;