Adds support for a Lit renderer (#665)

* Adds support for a Lit renderer

This adds `@astrojs/renderer-lit`. An experimental Lit renderer.

* Removed cached submodule, mistake

* Prevent globals clobbering

* Add docs on globals

1 files changed, 9 insertions, 0 deletions

diff --git a/packages/renderers/renderer-lit/client-shim.js b/packages/renderers/renderer-lit/client-shim.js
new file mode 100644
index 000000000..8dd75826f
--- /dev/null
+++ b/packages/renderers/renderer-lit/client-shim.js
@@ -0,0 +1,9 @@
+async function polyfill() {
+  const { hydrateShadowRoots } = await import('@webcomponents/template-shadowroot/template-shadowroot.js');
+  hydrateShadowRoots(document.body);
+}
+
+if(!(new DOMParser().parseFromString(`<p><template shadowroot="open"></template></p>`, 'text/html', {
+  includeShadowRoots: true
+}).querySelector('p')?.shadowRoot))
+  polyfill();
\ No newline at end of file