first draft

codemod-com · AugustinMauroy · Jul 14, 2025 · Jul 14, 2025 · Jul 14, 2025 · Jul 14, 2025
commit fe9d7b8c0f2f43a1bd3c5cc75cd7e4c6bf956a04
diff --git a/packages/codemod-standalone/README.md b/packages/codemod-standalone/README.md
@@ -0,0 +1,41 @@
+# Codemod Standalone
+
+## Usage
+
+```ts
+import { registerCodemod } from "@codemod-com/codemod-standalone";
+import type { SgRoot } from "@ast-grep/napi";
+
+// Work with `npx codemod@next`
+export default async function transform(root: SgRoot): Promise<string> {
+  const rootNode = root.root();
+
+  const nodes = rootNode.findAll({
+    rule: {
+      any: [
+        { pattern: "console.log($ARG)" },
+        { pattern: "console.debug($ARG)" },
+      ]
+    },
+  });
+
+  const edits = nodes.map(node => {
+    const arg = node.getMatch("ARG").text();
+    return node.replace(`logger.log(${arg})`);
+  });
+
+  const newSource = rootNode.commitEdits(edits);
+  return newSource;
+}
+
+// Register the codemod to use as `node src/transform.ts`
+registerCodemod(transform, {
+  language: 'typescript',
+});
+```
+
+## Command Line Usage
+
+```bash
+node src/transform.ts --input <glob> --exclude <glob> 
+```
diff --git a/packages/codemod-standalone/package.json b/packages/codemod-standalone/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "@codemod-com/codemod-standalone",
+  "author": "Augustin Mauroy",
+  "version": "0.0.1",
+  "description": "The utilities used across Codemod.com packages",
+  "type": "module",
+  "main": "./dist/index.js",
+  "module": "./dist/index.js",
+  "types": "./dist/index.d.ts",
+  "files": ["./dist", "README.md", "tsconfig.json"],
+  "scripts": {
+    "build": "tsc"
+  },
+  "license": "Apache-2.0",
+  "devDependencies": {
+    "@types/node": "^24.0.0",
+    "@codemod-com/tsconfig": "workspace:*"
+  }
+}
diff --git a/packages/codemod-standalone/src/index.ts b/packages/codemod-standalone/src/index.ts
@@ -0,0 +1,85 @@
+import fs from "node:fs";
+import path from "node:path";
+import { parseArgs } from "node:util";
+import { isPromise } from "node:util/types";
+import { isMainThread } from "node:worker_threads";
+import { Lang, parse } from "@ast-grep/napi";
+import type { SgRoot } from "@ast-grep/napi";
+
+/**
+ * Default patterns to exclude from processing.
+ * These patterns typically include directories like node_modules and .git.
+ */
+const DEFAULT_EXCLUDE = ["**/node_modules/**", "**/.git/**"];
+
+/**
+ * Register a codemod transformation.
+ * This function is intended to be called in the main thread.
+ * It processes files or directories specified in the command line arguments,
+ * applies the provided transformation function to the AST of each file,
+ * and writes the transformed content back to the file.
+ *
+ * @param transform Function to transform the AST root.
+ * It can either return a string or a Promise that resolves to a string.
+ * @param language
+ * The programming language of the files to be processed.
+ */
+export function registerCodemod(
+  transform: ((root: SgRoot) => Promise<string>) | ((root: SgRoot) => string),
+  language: string,
+) {
+  if (!isMainThread) return; // break the function if not in the main thread
+
+  const astGrepLang = Lang[language as keyof typeof Lang];
+
+  if (!astGrepLang) throw new Error(`Unsupported language: ${language}`);
+
+  const { values } = parseArgs({
+    args: process.argv.slice(2),
+    options: {
+      // what should we process
+      input: {
+        type: "string",
+      },
+      // what should we exclude
+      exclude: {
+        type: "string",
+      },
+    },
+    allowPositionals: true,
+  });
+
+  if (!values.input)
+    throw new Error("Input file or directory path is required.");
+
+  const files = fs.globSync(values.input, {
+    exclude: values.exclude ? [values.exclude] : DEFAULT_EXCLUDE,
+  });
+
+  for (const file of files) {
+    const filePath = path.resolve(file);
+
+    if (!fs.existsSync(filePath)) {
+      console.error(`File not found: ${filePath}`);
+      continue;
+    }
+
+    const content = fs.readFileSync(filePath, "utf-8");
+    const root = parse(astGrepLang, content);
+    const result = transform(root);
+
+    if (isPromise(result)) {
+      result
+        .then((transformedContent) => {
+          fs.writeFileSync(filePath, transformedContent, "utf-8");
+          console.log(`Processed file: ${filePath}`);
+        })
+        .catch((err) => {
+          console.error(`Error processing file ${filePath}:`, err);
+        });
+    } else {
+      fs.writeFileSync(filePath, result, "utf-8");
+      console.log(`Processed file: ${filePath}`);
+    }
+  }
+}
diff --git a/packages/codemod-standalone/tsconfig.json b/packages/codemod-standalone/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "extends": "@codemod-com/tsconfig/lib.json",
+  "compilerOptions": {
+    "baseUrl": "./src",
+    "outDir": "./dist"
+  }
+}