# How Do You Prevent Install of “devDependencies” npm Modules for node.js (package.json)?

When using `npm install` in Node.js, by default, both regular dependencies and devDependencies specified in the `package.json` file are installed. If you want to install only production dependencies (excluding devDependencies), you can use the `--production` flag.

Here's how you can do it:

```bash
npm install --production
```

This command installs only the dependencies listed in the "dependencies" section of your `package.json` file, skipping the packages listed in the "devDependencies" section.

If you want to make this behavior the default for your project, you can set an environment variable:

```bash
export NODE_ENV=production
npm install
```

Or, on Windows:

```bash
set NODE_ENV=production
npm install
```

Setting `NODE_ENV` to "production" automatically skips installing devDependencies. This is because npm will assume you are deploying your application in production when `NODE_ENV` is set to "production".

Keep in mind that during development, you might still need to install devDependencies. If you switch back to development mode, ensure to unset or change `NODE_ENV` accordingly.

It's also worth noting that some tools and scripts may rely on packages listed in devDependencies even during development, so be cautious about excluding them in certain situations.