Function bundle

packages/svelte/scripts/generate-browser-support.ts:292–329

* Bundle an entry the way users receive it, so we scan the same code the * browser does. Mirrors `check-treeshakeability.js`. * * `entry_code` is virtual module source: typically `export * from * 'svelte/...'` for a runtime entry, or compiled fixture JS for a per-feature * scan. `silent` suppre

(entry_code: string, options: { silent?: boolean } = {})

 * fixture bundles where they're known and noisy.
 */
async function bundle(entry_code: string, options: { silent?: boolean } = {}): Promise<string> {
	const built = await rollup({
		input: '__entry__',
		plugins: [
			virtual({ __entry__: entry_code }),
			{
				name: 'resolve-svelte',
				resolveId(id: string) {
					if (id.startsWith('svelte')) {
						const entry = pkg.exports[id.replace('svelte', '.')];
						if (!entry) return;
						if (typeof entry === 'string') return path.resolve(pkg_dir, entry);
						const file = entry.browser ?? entry.default;
						if (file) return path.resolve(pkg_dir, file);
					}
				}
			},
			nodeResolve({ exportConditions: ['production', 'import', 'browser', 'default'] })
		],
		// Treat optional peers / Node-only branches as external so we only scan
		// code that actually runs in the browser.
		external: ['esm-env'],
		onwarn: options.silent
			? () => {}
			: (warning, handler) => {
					if (warning.code === 'CIRCULAR_DEPENDENCY') return;
					handler(warning);
				}
	});

	const { output } = await built.generate({ format: 'esm' });
	await built.close();

	return output
		.filter((chunk): chunk is OutputChunk => chunk.type === 'chunk')
		.map((chunk) => chunk.code)
		.join('\n');
}

/**
 * Read every compiler-emitted client file from the snapshot tests. These