chore: bring extra linting into appkit

packages/appkit/bin/appkit-lint.js

@@ -0,0 +1,129 @@
+#!/usr/bin/env node
+/**
+ * AST-based linting using ast-grep.
+ * Catches patterns that ESLint/TypeScript miss or handle poorly.
+ * Usage: npx appkit-lint
+ */
+import { parse, Lang } from "@ast-grep/napi";
+import fs from "node:fs";
+import path from "node:path";
+
+const rules = [
+  {
+    id: "no-double-type-assertion",
+    pattern: "$X as unknown as $Y",
+    message:
+      "Avoid double type assertion (as unknown as). Use proper type guards or fix the source type.",
+  },
+  {
+    id: "no-as-any",
+    pattern: "$X as any",
+    message:
+      'Avoid "as any" type assertion. Use proper typing or unknown with type guards.',
+    includeTests: false, // acceptable in test mocks
+  },
+  {
+    id: "no-array-index-key",
+    pattern: "key={$IDX}",
+    message:
+      "Avoid using array index as React key. Use a stable unique identifier.",
+    filter: (code) => /key=\{(idx|index|i)\}/.test(code),
+  },
+  {
+    id: "no-parse-float-without-validation",
+    pattern: "parseFloat($X).toFixed($Y)",
+    message:
+      "parseFloat can return NaN. Validate input or use toNumber() helper from shared/types.ts.",
+  },
+];
+
+function isTestFile(filePath) {
+  return (
+    /\.(test|spec)\.(ts|tsx)$/.test(filePath) || filePath.includes("/tests/")
+  );
+}
+
+function findTsFiles(dir, files = []) {
+  const entries = fs.readdirSync(dir, { withFileTypes: true });
+
+  for (const entry of entries) {
+    const fullPath = path.join(dir, entry.name);
+
+    if (entry.isDirectory()) {
+      if (["node_modules", "dist", "build", ".git"].includes(entry.name))
+        continue;
+      findTsFiles(fullPath, files);
+    } else if (entry.isFile() && /\.(ts|tsx)$/.test(entry.name)) {
+      files.push(fullPath);
+    }
+  }
+
+  return files;
+}
+
+function lintFile(filePath, rules) {
+  const violations = [];
+  const content = fs.readFileSync(filePath, "utf-8");
+  const lang = filePath.endsWith(".tsx") ? Lang.Tsx : Lang.TypeScript;
+  const testFile = isTestFile(filePath);
+
+  const ast = parse(lang, content);
+  const root = ast.root();
+
+  for (const rule of rules) {
+    // skip rules that don't apply to test files
+    if (testFile && rule.includeTests === false) continue;
+
+    const matches = root.findAll(rule.pattern);
+
+    for (const match of matches) {
+      const code = match.text();
+
+      if (rule.filter && !rule.filter(code)) continue;
+
+      const range = match.range();
+      violations.push({
+        file: filePath,
+        line: range.start.line + 1,
+        column: range.start.column + 1,
+        rule: rule.id,
+        message: rule.message,
+        code: code.length > 80 ? code.slice(0, 77) + "..." : code,
+      });
+    }
+  }
+
+  return violations;
+}
+
+function main() {
+  const rootDir = process.cwd();
+  const files = findTsFiles(rootDir);
+
+  console.log(`Scanning ${files.length} TypeScript files...\n`);
+
+  const allViolations = [];
+
+  for (const file of files) {
+    const violations = lintFile(file, rules);
+    allViolations.push(...violations);
+  }
+
+  if (allViolations.length === 0) {
+    console.log("No ast-grep lint violations found.");
+    process.exit(0);
+  }
+
+  console.log(`Found ${allViolations.length} violation(s):\n`);
+
+  for (const v of allViolations) {
+    const relPath = path.relative(rootDir, v.file);
+    console.log(`${relPath}:${v.line}:${v.column}`);
+    console.log(`  ${v.rule}: ${v.message}`);
+    console.log(`  > ${v.code}\n`);
+  }
+
+  process.exit(1);
+}
+
+main();

packages/appkit/package.json

@@ -28,7 +28,8 @@
     "./package.json": "./package.json"
   },
   "bin": {
-    "appkit-generate-types": "./bin/generate-types.js"
+    "appkit-generate-types": "./bin/generate-types.js",
+    "appkit-lint": "./bin/appkit-lint.js"
   },
   "scripts": {
     "build:package": "tsdown --config tsdown.config.ts",
@@ -40,6 +41,7 @@
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
+    "@ast-grep/napi": "^0.37.0",
     "@databricks/sdk-experimental": "^0.15.0",
     "@opentelemetry/api": "^1.9.0",
     "@opentelemetry/api-logs": "^0.208.0",