feat: change vendor package exports (#818)

* feat: change vendor package exports

This patch changes top-level exports for the vendor-specific
packages:
- `playwright-chromium`: now exports an object with a single `chromium`
field
- `playwright-wekbit`: now exports an object with a single `webkit`
- `playwright-firefox`: now exports an object with a single `firefox`

Fixes #814

* fix typo

* address comments

packages/playwright-chromium/index.js

@@ -13,4 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-module.exports = require('playwright-core').chromium;
+
+module.exports = {
+  ...require('playwright-core'),
+  // Keep exporting Chromium and nullify other browsers.
+  webkit: undefined,
+  firefox: undefined,
+}

packages/playwright-firefox/index.js

@@ -13,4 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-module.exports = require('playwright-core').firefox;
+
+module.exports = {
+  ...require('playwright-core'),
+  // Keep exporting firefox and nullify other browsers.
+  chromium: undefined,
+  webkit: undefined,
+}

packages/playwright-webkit/index.js

@@ -13,4 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-module.exports = require('playwright-core').webkit;
+
+module.exports = {
+  ...require('playwright-core'),
+  // Keep exporting webkit and nullify other browsers.
+  chromium: undefined,
+  firefox: undefined,
+}