When you add the recommendation from ota-meshi/eslint-plugin-astro#168 (comment)

You get "unsafe assignment of an error typed value" with `DEPRECATED__createDefaultProgram`

Author: alexrecuenco

eslint.config.mjs

@@ -17,10 +17,10 @@ export default [
   {
     languageOptions: {
       parserOptions: {
-        project: ["./tsconfig.json"],
+        project: ["./tsconfig.json", "./tsconfig.eslint.json"],
         // When typescript/eslint v8 comes out this will become projectService
         // https://github.com/typescript-eslint/typescript-eslint/issues/9141
-        // EXPERIMENTAL_useProjectService: true,
+        EXPERIMENTAL_useProjectService: true,
         DEPRECATED__createDefaultProgram: true,
         tsconfigRootDir: import.meta.dirname,
       },

eslint.jsx.d.ts

@@ -0,0 +1,14 @@
+import "astro/astro-jsx";
+declare namespace astroHTML.JSX {
+  Element = HTMLElement
+}
+// See https://stackoverflow.com/a/75543975 and https://github.com/ota-meshi/eslint-plugin-astro/issues/168#issuecomment-1439480332
+// See https://github.com/withastro/astro/blob/4d13cf031b2e4242e0055b48c09a80d69b9ed15d/packages/astro/astro-jsx.d.ts#L34-L37
+declare global {
+  type Element = HTMLElement;
+  namespace JSX {
+    // type Element = astroHTML.JSX.Element // We want to use this, but it is defined as any.
+    type Element = HTMLElement;
+    // type IntrinsicElements = astroHTML.JSX.IntrinsicElements;
+  }
+}

package.json

@@ -1,13 +1,14 @@
 {
-  "name": "",
+  "name": "astro-eslint-plugin-issue-report",
   "type": "module",
-  "version": "0.0.1",
+  "version": "0.0.2",
   "scripts": {
     "dev": "astro dev",
     "start": "astro dev",
     "build": "astro check && astro build",
     "preview": "astro preview",
-    "astro": "astro"
+    "astro": "astro",
+    "lint": "eslint ."
   },
   "dependencies": {
     "@astrojs/check": "^0.7.0",

src/pages/index.astro

@@ -25,14 +25,23 @@ const b = 0;
     const d: any = 1;
 
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    // Unsafe assignment of an error typed value
     const element = document.getElementById("myroot")!;
     // no error
     console.log(element.offsetLeft + 4);
     // error  Invalid operand for a '+' operation. Operands must each be a number or string. Got `any`  @typescript-eslint/restrict-plus-operands
-    console.log(element.offsetLeft += 4);
+    console.log((element.offsetLeft += 4));
     console.log(d);
     console.log("c");
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     const container = document.querySelector(".container")!;
     container.scrollLeft += 2;
+    function scrollRight() {
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+      const other = document.querySelector(".other")!;
+      const value = other.scrollLeft;
+      other.scrollLeft = value + 2;
+    }
+    scrollRight();
   </script>
 </html>

tsconfig.eslint.json

@@ -0,0 +1,17 @@
+// This allows linting all files, including those that are excluded from our typescript compilation
+{
+    "extends": "./tsconfig.json",
+    // WARN: If 'include' is changed on the main config, this file would overwrite it, so you should consider modifying this.
+    "include": [
+        "eslint.jsx.d.ts",
+        "**/*.json",
+        ".astro/**/*",
+        "src/**/*",
+        "bin/**/*",
+        "__tests__/**/*",
+        ".*.js",
+        "*.js",
+        ".*.ts",
+        "*.ts",
+    ],
+}

tsconfig.json

@@ -1,3 +1,4 @@
 {
-  "extends": "astro/tsconfigs/strict"
+  "extends": "astro/tsconfigs/strict",
+  "include": ["eslint.jsx.d.ts"]
 }