npm i vs npm ci: Understanding the Difference
Tags: webdev, beginners, programming, tutorial
Published: 2024-02-27 08:00:00

## Introduction:

In the world of JavaScript development, npm (Node Package Manager) is an indispensable tool for managing dependencies. Whether you're a seasoned developer or just starting out, understanding the nuances between npm commands is crucial for efficient project management. Two commonly used commands, `npm i` and `npm ci`, serve similar purposes but operate differently under the hood. In this blog post, we'll delve into the differences between `npm i` and `npm ci` to help you make informed decisions when managing your projects' dependencies.

**What is `npm i`?**

The `npm i` command, short for npm install, is likely the most familiar and frequently used command for installing dependencies in a Node.js project. When you run `npm i`, npm fetches and installs all the dependencies listed in the project's `package.json` file, including their transitive dependencies, and stores them in the `node_modules` directory.

For example:

```bash
npm install
```

**What is `npm ci`?**

`npm ci` stands for npm clean install. It was introduced as a more efficient alternative to `npm i` for continuous integration (CI) environments, where reproducibility and speed are paramount. Unlike `npm i`, which may execute additional logic such as running npm scripts and saving the dependencies to `package-lock.json`, `npm ci` is designed to be deterministic and strictly adhere to the dependencies specified in the `package-lock.json` or `npm-shrinkwrap.json` file.

For example:

```bash
npm ci
```

**Differences:**

1. **Speed**: `npm ci` is generally faster than `npm i` because it skips certain steps like running lifecycle scripts and updating `package-lock.json` or `npm-shrinkwrap.json`.

2. **Reproducibility**: `npm ci` ensures that installations are deterministic by installing dependencies exactly as specified in the lock file. This guarantees consistent builds across different environments.

3. **Environment**: While `npm i` is suitable for development environments and situations where you might want to update or add dependencies, `npm ci` is best suited for CI/CD pipelines, production deployments, or situations where you need to ensure a clean, reproducible installation of dependencies without modification.

4. **Side Effects**: `npm i` can potentially have side effects such as running post-install scripts or updating lock files, whereas `npm ci` strictly installs dependencies without executing any scripts or altering lock files.

5. **Use Cases**: Use `npm i` when working on local development, adding or updating dependencies, or when you're not concerned about strict reproducibility. Reserve `npm ci` for automated environments like CI/CD pipelines or production deployments where you need consistent, fast, and reliable dependency installations.

**Key Differences:**

| Feature | npm i | npm ci |
|---|---|---|
| **Source** | `package.json` (flexible) | `package-lock.json` (strict) |
| **Behavior** | Updates existing dependencies | Installs exact versions |
| **Modifies files** | May update `package-lock.json` | Does not modify files |
| **Use case** | Development (flexibility) | CI/CD, Deployment (consistency) |

**Choosing the Right Tool:**

* Use `npm i` during development for its flexibility in managing and experimenting with dependencies.
* Use `npm ci` in CI/CD pipelines and deployments to ensure consistent and predictable builds and deployments across environments.

By understanding the distinctions between `npm i` and `npm ci`, you can make informed decisions, manage your dependencies effectively, and streamline your Node.js development workflow.

## Conclusion:

Understanding the differences between `npm i` and `npm ci` empowers JavaScript developers to choose the appropriate command based on their specific requirements. While `npm i` is versatile and suitable for general development tasks, `npm ci` shines in environments where reproducibility and speed are critical, such as continuous integration setups and production deployments. By leveraging the right npm command for the job, developers can streamline their workflows and ensure consistent, reliable dependency management in their projects.