feat(@astrojs/react): export renderer for easy loading (#11234)

* wip

* feat(@astrojs/react): export `renderer` for easy loading

* restore change

* chore: address feedback

* revert changes

* revert changes to react integration

* update changeset

1 files changed, 34 insertions, 0 deletions

diff --git a/packages/integrations/react/src/version.ts b/packages/integrations/react/src/version.ts
new file mode 100644
index 000000000..dc3a7a85a
--- /dev/null
+++ b/packages/integrations/react/src/version.ts
@@ -0,0 +1,34 @@
+import { version as ReactVersion } from 'react-dom';
+
+export type SupportedReactVersion = keyof typeof versionsConfig;
+export type ReactVersionConfig = (typeof versionsConfig)[SupportedReactVersion];
+
+export function getReactMajorVersion(): number {
+	const matches = /\d+\./.exec(ReactVersion);
+	if (!matches) {
+		return NaN;
+	}
+	return Number(matches[0]);
+}
+
+export function isUnsupportedVersion(majorVersion: number) {
+	return majorVersion < 17 || majorVersion > 19 || Number.isNaN(majorVersion);
+}
+
+export const versionsConfig = {
+	17: {
+		server: '@astrojs/react/server-v17.js',
+		client: '@astrojs/react/client-v17.js',
+		externals: ['react-dom/server.js', 'react-dom/client.js'],
+	},
+	18: {
+		server: '@astrojs/react/server.js',
+		client: '@astrojs/react/client.js',
+		externals: ['react-dom/server', 'react-dom/client'],
+	},
+	19: {
+		server: '@astrojs/react/server.js',
+		client: '@astrojs/react/client.js',
+		externals: ['react-dom/server', 'react-dom/client'],
+	},
+};