Nodemon

3.1.14 · active · verified Sat Apr 18

Nodemon is a development utility that automatically restarts Node.js applications when file changes are detected in the directory. It serves as a replacement wrapper for the `node` command, requiring no code modifications to integrate. The current stable version is 3.1.14, and the project maintains an active release cadence, frequently publishing minor updates and bug fixes.

Common errors

```
nodemon: command not found
```
cause Nodemon is not installed globally or is installed locally and not executed via `npx` or an npm script.

fix Install globally: `npm install -g nodemon`. If installed locally, run with `npx nodemon your-app.js` or via an npm script.
```
script.start with missing file
```
cause Nodemon attempted to start a script specified in `package.json` (via `main` or `scripts.start`) or on the command line, but the file does not exist or the path is incorrect.

fix Ensure the script file exists at the specified path and that the `main` or `scripts.start` entry in `package.json` is correct.
```
Nodemon is not watching nested paths or subdirectories for changes.
```
cause This could be due to an older version of Nodemon (fixed in v3.1.6) or an incorrect `watch` or `ignore` configuration in `nodemon.json`.

fix Update Nodemon to the latest version (`npm update nodemon`). Verify your `nodemon.json` does not accidentally ignore the directories you want to watch or explicitly configure `"watch": ["src/"]`.
```
TypeError: Property 'restart' does not exist on type 'Nodemon' or similar TypeScript type errors related to Nodemon configuration options like 'ignore'.
```
cause Your `@types/nodemon` package is outdated or incompatible with your installed `nodemon` version, or there's a missing type definition for a newer feature.

fix Update Nodemon and its corresponding TypeScript types: `npm update nodemon @types/nodemon`.
```
Nodemon is not detecting file changes on Windows.
```
cause There are known platform-specific issues with file system watching on Windows that have been addressed in recent Nodemon versions.

fix Update Nodemon to the latest version (`npm update nodemon`) to ensure you have the most recent fixes for Windows compatibility.

Warnings

gotcha When installing Nodemon locally (`npm install --save-dev nodemon`), the `nodemon` command will not be directly available in your system's PATH. You must run it via an npm script or by using `npx nodemon`.
Fix: If installed locally, use `npx nodemon your-app.js` or define an npm script like `"start": "nodemon your-app.js"`.
gotcha Nodemon is a command-line wrapper. You should replace `node` with `nodemon` when executing your script, e.g., `nodemon your-app.js`. Do not try to run it as `node nodemon your-app.js`.
Fix: Always use `nodemon` as the primary command to launch your application, passing your application script and arguments directly to `nodemon`.
gotcha Nodemon allows configuration through command-line arguments, local `nodemon.json`, and global `nodemon.json` files. Command-line arguments always take precedence over local config, which in turn overrides global config.
Fix: Be aware of this precedence when troubleshooting configuration issues. Check command-line args first, then local `nodemon.json`, then global `nodemon.json`.
gotcha If your `package.json` has a `main` property or a `scripts.start` command, Nodemon will automatically attempt to use that script if no specific file is provided on the command line. This can lead to running a different script than expected.
Fix: Explicitly specify the script you want to run (e.g., `nodemon server.js`) or verify that your `package.json` `main` or `scripts.start` points to the correct entry file.
gotcha Nodemon is designed as a command-line tool and is not intended for direct `import` or `require` into your application code. It operates as an external process manager.
Fix: Do not attempt to import or require `nodemon` within your Node.js application files. Use it exclusively from the command line or through npm scripts.

Install

npm install nodemon npm
yarn add nodemon yarn
pnpm add nodemon pnpm

Quickstart

Starts your TypeScript application using Nodemon, which will automatically restart the process whenever changes are detected in your project files, typically within the `src` directory.

npx nodemon ./src/index.ts

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