feat(configs/oxlint): add linter

configs/oxlint/src/compose.ts

@@ -0,0 +1,103 @@
+import type { OxlintConfig } from './types';
+
+/**
+ * Deep merge two objects. Arrays are concatenated, objects are recursively merged.
+ */
+function deepMerge(target: Record<string, unknown>, source: Record<string, unknown>): Record<string, unknown> {
+  const result = { ...target };
+
+  for (const key of Object.keys(source)) {
+    const targetValue = target[key];
+    const sourceValue = source[key];
+
+    if (
+      typeof targetValue === 'object' && targetValue !== null && !Array.isArray(targetValue)
+      && typeof sourceValue === 'object' && sourceValue !== null && !Array.isArray(sourceValue)
+    ) {
+      result[key] = deepMerge(
+        targetValue as Record<string, unknown>,
+        sourceValue as Record<string, unknown>,
+      );
+    }
+    else {
+      result[key] = sourceValue;
+    }
+  }
+
+  return result;
+}
+
+/**
+ * Compose multiple oxlint configurations into a single config.
+ *
+ * - `plugins` — union (deduplicated)
+ * - `categories` — later configs override earlier
+ * - `rules` — later configs override earlier
+ * - `overrides` — concatenated
+ * - `env` — merged (later overrides earlier)
+ * - `globals` — merged (later overrides earlier)
+ * - `settings` — deep-merged
+ * - `ignorePatterns` — concatenated
+ *
+ * @example
+ * ```ts
+ * import { compose, base, typescript, vue } from '@robonen/oxlint';
+ * import { defineConfig } from 'oxlint';
+ *
+ * export default defineConfig(
+ *   compose(base, typescript, vue, {
+ *     rules: { 'eslint/no-console': 'off' },
+ *   }),
+ * );
+ * ```
+ */
+export function compose(...configs: OxlintConfig[]): OxlintConfig {
+  const result: OxlintConfig = {};
+
+  for (const config of configs) {
+    // Plugins — union with dedup
+    if (config.plugins?.length) {
+      result.plugins = Array.from(new Set([...(result.plugins ?? []), ...config.plugins]));
+    }
+
+    // Categories — shallow merge
+    if (config.categories) {
+      result.categories = { ...result.categories, ...config.categories };
+    }
+
+    // Rules — shallow merge (later overrides earlier)
+    if (config.rules) {
+      result.rules = { ...result.rules, ...config.rules };
+    }
+
+    // Overrides — concatenate
+    if (config.overrides?.length) {
+      result.overrides = [...(result.overrides ?? []), ...config.overrides];
+    }
+
+    // Env — shallow merge
+    if (config.env) {
+      result.env = { ...result.env, ...config.env };
+    }
+
+    // Globals — shallow merge
+    if (config.globals) {
+      result.globals = { ...result.globals, ...config.globals };
+    }
+
+    // Settings — deep merge
+    if (config.settings) {
+      result.settings = deepMerge(
+        (result.settings ?? {}) as Record<string, unknown>,
+        config.settings as Record<string, unknown>,
+      );
+    }
+
+    // Ignore patterns — concatenate
+    if (config.ignorePatterns?.length) {
+      result.ignorePatterns = [...(result.ignorePatterns ?? []), ...config.ignorePatterns];
+    }
+  }
+
+  return result;
+}