authors	brunocroh

DEP0138: process.mainModule to require.main

Replaces deprecated process.mainModule with require.main in CommonJS modules.

Usage

Run this codemod with:

npx codemod @nodejs/process-main-module

Examples

Example 1

Direct property access:

-if (process.mainModule === module) {
+if (require.main === module) {
   // cli thing
 } else {
   // module thing
 }

Example 2

mainModule destructured from process — the destructuring is removed and all usages are replaced with require.main:

-const { mainModule } = process;
-
-if (mainModule === module) {
-  console.log(mainModule.filename);
+if (require.main === module) {
+  console.log(require.main.filename);
 }

Example 3

mainModule destructured from a require("node:process") call alongside other bindings — only mainModule is removed from the destructure; the remaining bindings are preserved:

-const { mainModule, env, cwd } = require("node:process");
+const { env, cwd } = require("node:process");

-if (mainModule === module) {
+if (require.main === module) {
   console.log(env, cwd);
 }