core: Flesh out ESLint package.

packages/eslint-config/index.js

@@ -0,0 +1,54 @@
+import eslint from "@eslint/js";
+import { reactConfig } from "@goauthentik/eslint-config/react-config";
+import { typescriptConfig } from "@goauthentik/eslint-config/typescript-config";
+import litconf from "eslint-plugin-lit";
+import wcconf from "eslint-plugin-wc";
+import tseslint from "typescript-eslint";
+
+// @ts-check
+
+/**
+ * @typedef ESLintPackageConfigOptions Options for creating package ESLint configuration.
+ * @property {string[]} [ignorePatterns] Override ignore patterns for ESLint.
+ * @property {import("typescript-eslint").ConfigWithExtends} [overrides] Additional ESLint rules
+ */
+
+/**
+ * @type {string[]} Default Ignore patterns for ESLint.
+ */
+export const DefaultIgnorePatterns = [
+    // ---
+    "**/*.md",
+    "**/.yarn",
+    "**/out",
+    "**/dist",
+];
+
+/**
+ * Given a preferred package name, creates a ESLint configuration object.
+ *
+ * @param {ESLintPackageConfigOptions} options The preferred package configuration options.
+ *
+ * @returns The ESLint configuration object.
+ */
+export function createESLintPackageConfig({
+    ignorePatterns = DefaultIgnorePatterns,
+    overrides = {},
+} = {}) {
+    return tseslint.config(
+        {
+            ignores: ignorePatterns,
+        },
+
+        eslint.configs.recommended,
+        ...tseslint.configs.recommended,
+        eslint.configs.recommended,
+        wcconf.configs["flat/recommended"],
+        litconf.configs["flat/recommended"],
+
+        ...reactConfig,
+        ...typescriptConfig,
+
+        overrides,
+    );
+}