Sprinkled a little tsconfig.json from astro. Probably needs to be updated. I don't think we're using TSX, for instance.

tsconfig.base.json

@@ -0,0 +1,32 @@
+{   // Copied from https://github.com/withastro/astro/blob/main/packages/astro/tsconfigs/base.json
+    "$schema": "https://json.schemastore.org/tsconfig",
+    "compilerOptions": {
+      // Enable top-level await, and other modern ESM features.
+      "target": "ESNext",
+      "module": "ESNext",
+      // Enable module resolution without file extensions on relative paths, for things like npm package imports.
+      "moduleResolution": "Bundler",
+      // Allow importing TypeScript files using their native extension (.ts(x)).
+      "allowImportingTsExtensions": true,
+      // Enable JSON imports.
+      "resolveJsonModule": true,
+      // Enforce the usage of type-only imports when needed, which helps avoiding bundling issues.
+      "verbatimModuleSyntax": true,
+      // Ensure that each file can be transpiled without relying on other imports.
+      // This is redundant with the previous option, however it ensures that it's on even if someone disable `verbatimModuleSyntax`
+      "isolatedModules": true,
+      // Astro directly run TypeScript code, no transpilation needed.
+      "noEmit": true,
+      // Report an error when importing a file using a casing different from another import of the same file.
+      "forceConsistentCasingInFileNames": true,
+      // Properly support importing CJS modules in ESM
+      "esModuleInterop": true,
+      // Skip typechecking libraries and .d.ts files
+      "skipLibCheck": true,
+      // Allow JavaScript files to be imported
+      "allowJs": true,
+      // Allow JSX files (or files that are internally considered JSX, like Astro files) to be imported inside `.js` and `.ts` files.
+      "jsx": "preserve"
+    }
+  }
+  

tsconfig.json

@@ -0,0 +1,7 @@
+{
+    "extends": "astro/tsconfigs/strict",
+    "compilerOptions": {
+      "jsx": "react-jsx",
+      "jsxImportSource": "react"
+    }
+  }

tsconfig.strict.json

@@ -0,0 +1,8 @@
+{   // Copied from https://github.com/withastro/astro/blob/main/packages/astro/tsconfigs/strict.json
+    "$schema": "https://json.schemastore.org/tsconfig",
+    "extends": "./base.json",
+    "compilerOptions": {
+      // Enable strict mode. This enables a few options at a time, see https://www.typescriptlang.org/tsconfig#strict for a list.
+      "strict": true
+    }
+}

tsconfig.strictest.json

@@ -0,0 +1,24 @@
+{   // Copied from https://github.com/withastro/astro/blob/main/packages/astro/tsconfigs/strictest.json
+    "$schema": "https://json.schemastore.org/tsconfig",
+    "extends": "./strict.json",
+    "compilerOptions": {
+      // Report errors for fallthrough cases in switch statements
+      "noFallthroughCasesInSwitch": true,
+      // Force functions designed to override their parent class to be specified as `override`.
+      "noImplicitOverride": true,
+      // Force functions to specify that they can return `undefined` if a possible code path does not return a value.
+      "noImplicitReturns": true,
+      // Report an error when a variable is declared but never used.
+      "noUnusedLocals": true,
+      // Report an error when a parameter is declared but never used.
+      "noUnusedParameters": true,
+      // Force the usage of the indexed syntax to access fields declared using an index signature.
+      "noUncheckedIndexedAccess": true,
+      // Report an error when the value `undefined` is given to an optional property that doesn't specify `undefined` as a valid value.
+      "exactOptionalPropertyTypes": true,
+      // Report an error for unreachable code instead of just a warning.
+      "allowUnreachableCode": false,
+      // Report an error for unused labels instead of just a warning.
+      "allowUnusedLabels": false
+    }
+  }